computer tips and tricks, Tips and Tricks, windows tips, خدع الكمبيوتر, أسرار الكمبيوتر

suddenly,no wireless access

2012-03-02T05:54:00.002-08:00

suddenly no access to wireless network in our LAN ,my laptop is inside domain.and i am sure i didn't change my password.
what happenned?
remember that you are notified to change the password and you didn't !
just changed the password and it is OK!.

Shift key and mouse click

2012-02-24T06:17:00.000-08:00

Many text editors and programs allow you to highlight all or portions of text using the Shift key and the mouse. For example, place the cursor at the beginning of a paragraph, hold down the Shift key and click at the end of the paragraph to highlight the full paragraph.

tip from computerhope.com

Basic networking troubleshooting commands

2011-12-24T06:10:00.000-08:00

From the command prompt:

- ipconfig( ifconfig in unix systems) command: tells you some basic information about your computer’s network card’s configuration.(your device IP addres,gateway,...)
-Ping command: check the connectivity to a destintion .
-tracert (traceroute in unix systems) command: shows the path your data take to reach the destination.

From the internet explorer "tools" menu"
check the proxy settings:
Tools>>Internet Options >> Connections >>LAN Settings

another windows tip

2011-11-15T03:50:00.000-08:00

another windows tip

create a new folder ,try to name it CON
what is the result , Why?
waiting comments!

Computer maintenance, computer speed

2011-10-28T11:52:00.000-07:00

Important Computer Maintenance steps :

1- Disk Defragmentation
2-Scandisk
3-Cleaning Registry
4-Delete files you do not need
5-Delete Temp files manually
6-Remove programs you do not need
7- Windows Update

on screen keyboard

2011-09-16T06:46:00.000-07:00

HI
new trick:
How to start (launch) the on screen keyboard?

simply : go to start>>RUN and write OSK

the on screen KB will pop up and ready to use!

VERY INTERESTING INTERNET TIPS, create your own google search page

2011-08-06T02:35:00.000-07:00

ENJOY THESE TIPS:

1-if you like to make your name as google LOGO :
Go to http://www.goglogo.com/, write your name in the textbox ten make it your homepage ,congratulations ,,,you've made your own google search page.

2-If you like see yourseklf destroying others websites -but not actually doing so- try the below link and in the specified textbox starting with http write the target website, nice to trick your friends :):
http://www.bored.com/destroysites/

Repeat the last action in Microsoft Word and Excel

2011-06-03T04:45:00.000-07:00

Using the F4 key in Microsoft Office 2000 and above allows the user to repeat the last used action.

enable telnet on windows 7, telnet in windows 7

2011-05-16T13:42:00.000-07:00

if you try using telnet on windows 7 and the commmand is not recognized, then you can turn the service on as follows:

1- Go to "Control Panel"
2- choose "programs and features"
3- on the left side you find an option " turn windows features ON OFF"
4- choose telnet service

password protect excel file, protect excel sheet

2011-05-14T05:46:00.000-07:00

when you password protect the excel file, you can do this for two options , one pasword for OPEN and one for MODIFY.

Protecting the File

From the File menu, select Save As...The Save As dialog box appears.
From the Tools pull-down list, select General Options...
The General Options dialog box appears.
in the Password to open text box, type a password
in the Password to modify text box, type a password
OPTIONAL: If you like Excel to recommend that this file be opened as a read-only file each time it is opened, select Read-only recommended
Click OKThe Confirm Password dialog box appears.
In the Reenter password to modify text box, type the password(s) in the order of the password(s) that you typed in the Save Options dialog box
Click OK
Click SAVE

Unprotecting the File

If you no longer need to password-protect the file, you can remove the password.

Open the file
From the File menu, select Save As…
In the Save As dialog box, from the Tools pull-down list, select General Options...
In the Password to open text box, select the text » press [Delete]
In the Password to modify text box, select the text » press [Delete]
Click OKThe file is no longer password protected.
To save the file, click SAVE
Click YES

umdmgr.exe, umdmgr, kill umdmgr process

2011-05-01T08:20:00.000-07:00

-When i shut down the PC i see a window with title: umdmgr.exe, and it appears many times before the shut down succeed.
OR: my computer has UMDMGR shall i remove it?

Answer:
Yes, remove it, and this problem can be solved by having your antivirus and antimalware updated and performing a full scan, you should be able to remove it.

Other Solution
REMOVE IT. This is a trojan.remove it manually or with an antivirus. Here is how to do it manually. Go to My computer and double click on the c: After that you will see folders open the WINDOWS folder, now that the windows folder is open go to the SYSTEM32 folder, under that folder you would see the umdmgr.exe. Right click on it and remove it, and you're done.

Speed up your browsing of Windows 2000 & XP machines

2011-04-09T05:02:00.000-07:00

Speed up your browsing of Windows 2000 & XP machines

Here's a great tip to speed up your browsing of Windows XP machines. Its actually a fix to a bug installed as default in Windows 2000 that scans shared files for Scheduled Tasks. And it turns out that you can experience a delay as long as 30 seconds when you try to view shared files across a network because Windows 2000 is using the extra time to search the remote computer for any Scheduled Tasks. Note that though the fix is originally intended for only those affected, Windows 2000 users will experience that the actual browsing speed of both the Internet & Windows Explorers improve significantly after applying it since it doesn't search for Scheduled Tasks anymore. Here's how :

Open up the Registry and go to :
HKEY-LOCAL-MACHINE/Software/Microsoft/Windows/Current Version/Explorer/RemoteComputer/NameSpace
Under that branch, select the key :
{D6277990-4C6A-11CF-8D87-00AA0060F5BF}
and delete it.
This is key that instructs Windows to search for Scheduled Tasks. If you like you may want to export the exact branch so that you can restore the key if necessary.
This fix is so effective that it doesn't require a reboot and you can almost immediately determine yourself how much it speeds up your browsing processes.

How to export the Outlook address book

2011-04-09T04:58:00.000-07:00

How to export the Outlook address book

Looking for a way to export your Outlook Address Book to another program? Outlook 97 and Outlook 98 doesn't come with a built-in method to export the address book, but if you have Outlook Express 4.x here's an indirect method:

Run Outlook Express 4.x (if you don't already have it, install Explorer 4.x full version)
Select "File | Import | Address Book..." from the main menu
Select "Microsoft Exchange Personal Address Book"
Click "Import" and click "Close" once the importing is completed

To export the address book:
Select "File | Export | Address Book..." from the main menu
Select "Text File (Comma Separated Values)"
Click "Export"
Type a file name in the "Save exported file as" input box.

For example type, "C:\MYADRBOK.CSV"

Click "Next"

Optionally select the fields you wish to export and click "Finish"

Click "Close" once the exporting is completed

You're now ready to import the newly exported Outlook address book (C:\MYADRBOK.CSV file for example) into the program you were trying to export to. CSV (comma separated values) text files are supported by almost all programs with the ability to import information from external programs. Refer to the documentation for further instructions.

Microsoft Outlook 2003 tips and tricks

2011-03-25T07:51:00.000-07:00

Microsoft Outlook 2003 tips and tricks:

Set a reminder to reply to a message Right-click the message you want to set the reminder for, point to Follow Up, and then click Add Reminder. In the Due By list, click the date when you have to complete the reply. In the second list, click a time. In the Flag color list, click the flag color you want, and then click OK.
Add your own words to a follow-up flag for a new message Click the Message Flag button and then type the text you want in the Flag to box.
Send a message to multiple people without revealing other recipients' identities To send a message to someone without other recipients of the message knowing, use the Bcc line in the message. Bcc stands for blind carbon copy. If you add someone's name to the Bcc line, a copy of the message is sent to that person, but his or her name is not visible to other recipients.

Protecting Yourself From Spam, block an email address in yahoo mail, prevent Spam on yahoo

2011-03-12T01:06:00.000-08:00

Protecting Yourself From Spam, block an email address in yahoo mail, prevent Spam on yahoo:

Here is how to do it :

-In the upper-right corner of your Yahoo! Mail page, click the Options link, then select Mail Options from the menu.
-Click the Spam link .
-In the Add a blocked address box, type the email address you want to block, then click the Add button.
Note:To block email messages from the whole domain (ex: baddomain.com), type the domain in this box.
-To remove or unblock an address or domain from your list, select the entry to remove, then click the Remove button.

Enjoy!

Nokia Secret Codes, secret codes for Nokia

2011-03-12T00:56:00.000-08:00

Nokia Secret Codes:

*#06# For checking the IMEI(international Mobile Equipment Identity)
*#7780# Reset to factory defaults
*#0000# To view software version
*#2820# the Bluetooth device address
*#746025625# Sim clock allowed status

#PW+1234567890+1# = GIVES PROVIDER-LOCK STATUS

#PW+1234567890+2# = GIVES NETWORK-LOCK STATUS

#PW+1234567890+3# = GIVES COUNTRY-LOCK STATUS

#PW+1234567890+4# = GIVES SIM-CARD-LOCK STATUS.

*#92702689# (*#WAR0ANTY#) to enter the service menu type-

Enjoy!

Speed up Internet Surfing

2011-03-05T02:45:00.000-08:00

Speed up Internet Surfing

You can increase the speed for surfing the internet in several way but i want to mention the following easy way. The Windows XP normally limit the internet speed by reserving a part of bandwidth. In this easy way I just only change the Bandwidth Limit value to zero.

Go to Start > Run.
Type gpedit.msc then click OK. Windows XP will lead you to Group Policy page.
In your left hand of the page, click on Administrative Templates which is under Computer Configuration.
Double click Network which is in the right hand of the page.
Double click QoS Packet Scheduler.

Double click Limit reservable bandwidth.
Select the Enabled option.
Now you are able to see the message Bandwidth Limit (%): . In this box let you change the value to zero and then click OK.

Finding the sender IP address, yahoo, hotmail, Gmail

2011-03-05T02:41:00.000-08:00

1-Finding the sender IP address(HOTMAIL)

-Log into your Hotmail account with your username and password.
- Click on the Mail tab on the top.
-Open the mail.
-If you do not see the headers above the mail message, your headers are not displayed . To display the headers,

* Click on Options on the top-right corner
* In the Mail Options page, click on Mail Display Settings
* In Message Headers, make sure Advanced option is checked.
* Click on Ok button

* Go back to the mails and open that mail.
- If you find a header with X-Originating-IP: followed by an IP address, that is the sender’s IP address
* Hotmail headers : Daniel ,In this case the IP address of the sender is [68.34.60.59]. This is be the IP address of the sender.
- If you find a header with Received: from followed by a Gmail proxy like this
* Hotmail headers : Daniel
* Look for Received: from followed by IP address within square brackets[]. In this case, the IP address of the sender is [69.140.7.58].
-Or else if you have headers like this
* Hotmail headers : Daniel
* Look for Received: from followed by IP address within square brackets[].
In this case, the IP address of the sender is [61.83.145.129] .
-If you have multiple Received: from headers, eliminate the ones that have proxy.anyknownserver.com.

2-Finding IP Address of the sender in Yahoo Mail

- Log into your Yahoo! mail with your username and password
- Click on Inbox or whichever folder you have stored your mail.
-Open the mail.
-If you do not see the headers above the mail message, your headers are not displayed . To display the headers,
* Click on Options on the top-right corner
* In the Mail Options page, click on General Preferences
* Scroll down to Messages where you have the Headers option
* Make sure that Show all headers on incoming messages is selected
* Click on the Save button
* Go back to the mails and open that mail.
- You should see similar headers like this:
* Yahoo! headers : Daniel.
- Look for Received: from followed by the IP address between square brackets [ ]. Here, it is 202.65.138.109.
- That is be the IP address of the sender!

3-Finding IP Address of the sender in Gmail

When you receive an email, you receive more than just the message. The email comes with headers that carry important information that can tell where the email was sent from and possibly who sent it. For that, you would need to find the IP address of the sender. The tutorial below can help you find the IP address of the sender.
* Log into your Gmail account with your username and password.
* Open the mail.
* To display the headers,
o Click on More options corresponding to that thread. You should get a bunch of links. Click on Show original
* You should get headers like this:
o Gmail headers : xyzw
* Look for Received: from followed by a few hostnames and an IP address between square brackets. In this case, it is A.B.C.D
* That is be the IP address of the sender!!

unix tips, convert man pages to text files, linux tips, solaris tips, How to replace text in multiple files, execute commands at specified times

2011-02-19T08:31:00.000-08:00

Hi
Below some important general unix tips:

How to run a command to a set of files (The while read command can handle names with spaces but you need to quote the variable after):
```
[unix]$ for i in `ls *mp3`; do cp $i $i.bak; done
```
```
[unix]$ ls *mp3 | while read i; do cp "$i" "$i with more spaces"; done
```

How to rename part of a file:

[unix]$ echo filename | sed 's/file/another/'

How to replace text in multiple files:

[unix]$ sed -e 's/oldtext/newtext/' -i file1 file2 file3 ...

How to delete lines matching a pattern in some files:

[unix]$ sed -e '/pattern/ d' -i file1 file2 file3 ...

How to change all letters to lowercase:
```
[unix]$ echo FilENamE | tr A-Z a-z
```
A good way to change all filenames in a directory to lowercase:
This handles a colored ls (hence the quotes around ls, but you can use any file list output, i.e. find) and names with spaces (hence the while read and not the for).
```
[unix]$ "ls" | while read name; do mv "$name" "`echo $name | tr A-Z a-z`"; done
```
How to convert man pages to text files:
```
[unix]$ man man | col -b
```

How to list all the open ports and programs:

[linux]$ netstat -apne --inet
[freebsd]$ sockstat

How to list all the open files and programs:
```
[linux]$ lsof
[freebsd]$ fstat
```
How to find information about an ip (i.e. 10.0.0.0):
```
[unix]$ host 10.0.0.0
[unix]$ dig -x 10.0.0.0
```
How to find information about an ip owner (i.e. 10.0.0.0):
```
[unix]$ whois -h whois.arin.net 10.0.0.0
```
How to find out the mailserver for an ip:
```
[unix]$ dig mx some.domain.name.net
```

How to generate a filename with yesterdays date (i.e. for logfiles/backups):

[linux]$ touch logfile-`date -dyesterday '+%Y-%m-%d'`
[freebsd]$ touch logfile-`date -v-1d '+%Y-%m-%d'`

Commands/options you should know about, read the man pages

tail - display the end of a file
head - display the beggining of a file
xargs - convert stdin to command line arguments
nmap - network scanner
watch (linux) - run a command periodically and watch the output
watch (freebsd) - monitor a tty
lsof - lists the open files
strace (linux) - trace the system calls of a program
truss (freebsd) - trace the system calls of a program
calc - command line calculator program
bc - another command line calculator program
dc - command line RPN calculator program
du - how much disk space is being used by something
df - disk free, how much free space there is
touch - creates an epty file or updates the timestamp on a file
diff - show the difference between 2 files
strings - show the strings in a file (useful for binaries)
file - tells you what type a file is
finger - find out information about users
w / who - who is currently on the machine and what are they doing
id - tells you who you are
uname - tells you basic information about the system.
whois - information about hosts
crontab - execute commands at specified times
last - last users to log into the system
mail - very basic mailer, useful for redirection
nice/renice - set the niceness ("priority") level of a program
nohup - leave a program running after logging off
screen - virtual terminal for leaving programs running
psnup - print multiple pages in one page
time - time the execution of a command
wc - word count, tells you the size in bytes, words and lines
which / whereis - locates commands
locate - locates files
whatis - gives brief summary of a comm
and
wget / fetch - get files off the net
talk - chat with other users on the system
write / wall - send messages to users of the system
zcat - cat gzipped files
ln - link files
sleep - wait a specified amount of time
md5sum (linux) - calculate the md5 signature of a file
md5 (freebsd) - calculate the md5 signature of a file
enscript - convert text files to ps
awk, sed - useful scripting programs
cat, echo, more/less, find, grep - you need to know these, it's not an option.

Resource: http://sluglug.ucsc.edu/~isolis/knowledge/unix-tips/

Access task manager without control-alt-delete

2011-02-11T11:44:00.000-08:00

Problem:
How to access task manager without control-alt-delete:

solution:

1-Option1:
right click on an empty area of your taskbar, and clicking on "Task Manager".

2-Option2:
Use the key combination: Ctrl+Shift+Esc

I hope this helps...

MS Excel adding problem, MS excel Summation problem

2011-02-11T11:31:00.000-08:00

Hi and welcome to the new Tip:
Problem:
One of my friends asked me "When i tried to add numbers like 1,2 and 5,5 i get an error message and icannot do it".

Solution:

use the dot instead of the comma . instead of , like this:
1.2+5.5 iinstead of 1,2 +5,5
================================================

Wrong form:

correct form:

fatal error 1603, excel error, Visual studio.net 2005 toolbox

2011-02-11T11:19:00.000-08:00

1-Problem:
Visual Studio 2005 -- Error code 1603 for this component means "Fatal error during installation:

example error:
[08/08/07,12:28:44] Microsoft Document Explorer 2005: [2] Error code 1603 for this component means "Fatal error during installation.

solution:

according to my case: i installed previously the Visual studio 2008 and uninstalled it. when i tried to install VS2005 the error 1603 "Fatal error" appeared. i removed all related files of the previous installation using "Add/Remove programs". and then i installed it successfully.

i found alot of other solutions ,it seeems for different-but related problems-, i mentioned them below:

http://support.microsoft.com/kb/834484
http://support.microsoft.com/kb/968749

Windows XP System Hangs Response , explorer.exe hack

2011-01-12T23:39:00.000-08:00

This trick is important when you don't like to reboot your computer when it hangs, you can follow these simple steps to 'reboot' your computer without 'rebooting' it.

Press CRTL + ALT + DEL

Goto the 'processes' tab and click explorer.exe once and then click 'end process'.

Now, click File > New Task and type explorer.exe

then you will see to the normal behaviour again. except if it is a major problem that needs restart.

how to open office 2007 files into Office 2003

2011-01-08T07:05:00.001-08:00

how to open office 2007 files into Office 2003

http://www.microsoft.com/downloads/details.aspx?FamilyId=941b3470-3ae9-4aee-8f43-c6bb74cd1466&displaylang=en

TIP takem from:tricksystem.com

Today tip will help you to resolve the compatibility issues between the Office 2003 and Office 2007. Because all programs in office 2003 used the old file extensions for its different programs. For example Word 2003 saved files with extension .doc, Excel 2003 with .xls and PowerPoint with .ppt. but on the other office 2007 used the new file extensions for its different programs. For example Word 2007 saved files with extension .docx, Excel 2007 with .xlsx and PowerPoint with .pptx. Now the problem is that when you will try to open office 2007 files into office 2003 and you will not open the file due to compatibility issues between both office versions. Microsoft provides a free compatibility pack to convert office 2007 documents to the office 2003 format. There are many third party free converter are available but here we are using Microsoft office compatibility pack.

Follow the given steps to download free Microsoft compatibility pack and install it.

To use this feature, you will need to be logged into your computer with administrative rights.

Visit the following link to download the Microsoft compatibility pack:

Using Loops in VBA in Microsoft Excel

2011-01-08T07:03:00.000-08:00

taken from: exceltip.com

Why Loops?

The purpose of a loop is to get Excel to repeat a piece of code a certain number of times. How many times the code gets repeated can be specified as a fixed number (e.g. do this 10 times), or as a variable (e.g. do this for as many times as there are rows of data).
Loops can be constructed many different ways to suit different circumstances. Often the same result can be obtained in different ways to suit your personal preferences. These exercises demonstrate a selection of different ways to use loops.
There are two basic kinds of loops, both of which are demonstrated here: Do…Loop and For…Next loops. The code to be repeated is placed between the key words.
Open the workbook VBA02-Loops.xls and take a look at the four worksheets. Each contains two columns of numbers (columns A and B). The requirement is to calculate an average for the numbers in each row using a VBA macro.
Now open the Visual Basic Editor (Alt+F11) and take a look at the code in Module1. You will see a number of different macros. In the following exercises, first run the macro then come and read the code and figure out how it did what it did.
You can run the macros either from the Visual Basic Editor by placing your cursor in the macro and pressing the F5 key, or from Excel by opening the Macros dialog box (ALT+F8) choosing the macro to run and clicking Run. It is best to run these macros from Excel so you can watch them as they work.

Exercise 1: Do… Loop Until…

The object of this macro is to run down column C as far as is necessary putting a calculation in each cell as far as is necessary.
On Sheet1 select cell C2 and run the macro Loop1.
Here's the code:
Sub Loop1()
' This loop runs until there is nothing in the next column
    Do
    ActiveCell.FormulaR1C1 = "=Average(RC[-1],RC[-2])"
    ActiveCell.Offset(1, 0).Select
    Loop Until IsEmpty(ActiveCell.Offset(0, 1))
End Sub
This macro places a formula into the active cell, and moves into the next cell down. It uses Loop Until to tell Excel to keep repeating the code until the cell in the adjacent column (column D) is empty. In other words, it will keep on repeating as long as there is something in column D.
Delete the data from cells C2:C20 and ready for the next exercise

Exercise 2: Do While… Loop

The object of this macro is to run down column C as far as is necessary putting a calculation in each cell as far as is necessary.
On Sheet1 select cell C2 and run the macro Loop2
Here's the code
Sub Loop2()
' This loop runs as long as there is something in the next column
    Do While IsEmpty(ActiveCell.Offset(0, 1)) = False
    ActiveCell.FormulaR1C1 = "=Average(RC[-1],RC[-2])"
    ActiveCell.Offset(1, 0).Select
    Loop
End Sub
This macro does the same job as the last one using the same parameters but simply expressing them in a different way. Instead of repeating the code Until something occurs, it does something While something is the case. It uses Do While to tell Excel to keep repeating the code while there is something in the adjacent column as opposed to until there is nothing there. The function IsEmpty = False means "Is Not Empty".
Delete the data from cells C2:C20 and ready for the next exercise

Exercise 3: Do While Not… Loop

The object of this macro is to run down column C as far as is necessary putting a calculation in each cell as far as is necessary.
On Sheet1 select cell C2 and run the macro Loop3.
Here's the code:
Sub Loop3()
' This loop runs as long as there is something in the next column
    Do While Not IsEmpty(ActiveCell.Offset(0, 1))
    ActiveCell.FormulaR1C1 = "=Average(RC[-1],RC[-2])"
    ActiveCell.Offset(1, 0).Select
    Loop
End Sub
This macro makes exactly the same decision as the last one but just expresses it in a different way. IsEmpty = False means the same as Not IsEmpty. Sometimes you can't say what you want to say one way so VBA often offers an alternative syntax.
Delete the data from cells C2:C20 and ready for the next exercise

Exercise 4: Including an IF statement

The object of this macro is as before, but without replacing any data that may already be there.
Move to Sheet2, select cell C2 and run the macro Loop4.
Here's the code:
Sub Loop4()
' This loop runs as long as there is something in the next column
' It does not calculate an average if there is already something in the cell
    Do
    If IsEmpty(ActiveCell) Then
        ActiveCell.FormulaR1C1 = "=Average(RC[-1],RC[-2])"
    End If
    ActiveCell.Offset(1, 0).Select
    Loop Until IsEmpty(ActiveCell.Offset(0, 1))
End Sub
The previous macros take no account of any possible contents that might already be in the cells into which it is placing the calculations. This macro uses an IF statement that tells Excel to write the calculation only if the cell is empty. This prevents any existing data from being overwritten. The line telling Excel to move to the next cell is outside the IF statement because it has to do that anyway.

Exercise 5: Avoiding Errors

This macro takes the IF statement a stage further, and doesn't try to calculate an average of cells that are empty.
First, look at the problem. Move to Sheet3, select cell C2 and run the macro Loop4.
Note that because some of the pairs of cells in columns A and B are empty, the =AVERAGE function throws up a #DIV/0 error (the Average function adds the numbers in the cells then divides by the number of numbers - if there aren't any numbers it tries to divide by zero and you can't do that!).
Delete the contents of cells C2:C6 and C12:C20. Select cell C2 and run the macro Loop5.
Here's the code:
Sub Loop5()
' This loop runs as long as there is something in the next column
' It does not calculate an average if there is already something in the cell
' nor if there is no data to average (to avoid #DIV/0 errors).
    Do
    If IsEmpty(ActiveCell) Then
        If IsEmpty(ActiveCell.Offset(0, -1)) And IsEmpty(ActiveCell.Offset(0, -2)) Then
            ActiveCell.Value = ""
        Else
            ActiveCell.FormulaR1C1 = "=Average(RC[-1],RC[-2])"
        End If
    End If
    ActiveCell.Offset(1, 0).Select
    Loop Until IsEmpty(ActiveCell.Offset(0, 1))
End Sub
Note that this time there are no error messages because Excel hasn't tried to calculate averages of numbers that aren't there.
In this macro there is a second IF statement inside the one that tells Excel to do something only if the cell is empty. This second IF statement gives excel a choice. Instead of a simple If there is an If and an Else. Here's how Excel reads its instructions…
"If the cell has already got something in, go to the next cell. But if the cell is empty, look at the corresponding cells in columns A an B and if they are both empty, write nothing (""). Otherwise, write the formula in the cell. Then move on to the next cell."

Exercise 6: For… Next Loop

If you know, or can get VBE to find out, how many times to repeat a block of code you can use a For… Next loop.
Move to Sheet4, select cell C2 and run the macro Loop6.
Here's the code:
Sub Loop6()
' This loop repeats for a fixed number of times determined by the number of rows
' in the range
    Dim i AsInteger
    For i = 1 To Selection.CurrentRegion.Rows.Count - 1
    ActiveCell.FormulaR1C1 = "=Average(RC[-1],RC[-2])"
    ActiveCell.Offset(1, 0).Select
    Next i
End Sub
This macro doesn't make use of an adjacent column of cells like the previous ones have done to know when to stop looping. Instead it counts the number of rows in the current range of data and uses the For… Next method to tell Excel to loop that number of times (minus one, because when VBA counts it starts at zero).

Exercise 7: Getting the Reference From Somewhere Else

Select cell G2 and run the macro Loop7.
Here's the code:
Sub Loop7()
' This loop repeats a fixed number of times getting its reference from elsewhere
    Dim i As Integer
    Dim intRowCount As Integer
    intRowCount = Range("A1").CurrentRegion.Rows.Count - 1
    For i = 1 To intRowCount
    ActiveCell.FormulaR1C1 = "=Average(RC[-5],RC[-6])"
    ActiveCell.Offset(1, 0).Select
    Next i
End Sub
You can get the reference for the number of loops from anywhere. This macro places a set of calculations in column G for a number of times dictated by the number of rows in the block of data starting with cell A1. The For… Next statement has been simplified a bit by first declaring a variable intRowCount and filling it with the appropriate information (how many rows in the block by A1). This variable gets used in the next line instead of a long line of code. This is just another example of doing the same job a different way.
If you wanted to construct a loop that always ran a block of code a fixed number of times, you could simply use an expression like:
            For i = 1 To 23

Exercise 8: About Doing Calculations…

All the previous exercises have placed a calculation into a worksheet cell by actually writing a regular Excel function into the cell (and leaving it there) just as if you had typed it yourself. The syntax for this is:
ActiveCell.FormulaR1C1 = “TYPE YOUR FUNCTION HERE”
These macros have been using:
ActiveCell.FormulaR1C1 = “=Average(RC[-5],RC[-6])”
Because this method actually places a function into the cell rather than a value, their results will change as the cells that they refer to change, just like regular functions – because they are regular functions. The calculating gets done in Excel because all that the macro did was to write the function.
If you prefer, you can get the macro to do the calculating and just write the result into the cell. VBA has its own set of functions, but unfortunately AVERAGE isn’t one of them. However, VBA does support many of the commoner Excel functions with its WorksheetFunction method.
On Sheet1 select cell C2 and run the macro Loop1.
Take a look at the cells you just filled in. Each one contains a function, written by the macro.
Now delete the contents from the cells C2:C20, select cell C2 and run the macro Loop8.
Here’s the code:
Sub Loop8()
    Do
    ActiveCell.Value = WorksheetFunction.Average(ActiveCell.Offset(0, -1).Value, _
         ActiveCell.Offset(0, -2).Value)
    ActiveCell.Offset(1, 0).Select
    Loop Until IsEmpty(ActiveCell.Offset(0, 1))

End Sub

Take a look at the cells you just filled in. This time there’s no function, just the value. All the calculating was done by the macro which then wrote the value into the cell.