Excel 2007 uses a highly incompatible .xlsx file format for saving files, making it difficult to share with friends and colleagues who don't have the same version. To change this:

Click the Office button in the top left
Click the Excel Options button
On the left-hand side, select Save
Change the Save files in this format drop down box to Excel 97 - 2003 Workbook
Click OK

Word 2007 uses a highly incompatible .docx file format for saving files, making it difficult to share with friends and colleagues who don't have the same version. To change this:

Click the Office button in the top left
Click the Word Options button
On the left-hand side, select Save
Change the Save files in this format drop down box to Word 97 - 2003 Document (*.doc)
Click OK

A Windows Messenger that comes with the Microsoft Windows XP as a Windows Component. It always appears on the status bar and remains in the Windows even you have download and installed new MSN Messenger, to remove this default messenger permanently form windows do that follow steps

1. Click on Start Menu > Run > type “control.exe” and hit enter
2. Double click on “Add or Remove Programes” icon
3. On the left side click on “Add/Remove Window Components” button
4. In this Window scroll down and uncheck the “Windows Messenger” check box, click next and you are done.
Screen Shot

use the following steps if you don't have your phone's modem driver.

1. Go to -> Control Panel -> Select Phone and Modem options.

2. Install a new modem on your computer. Do not allow the computer to detect a Plug and Play modem. Instead, select the Standard 33600 modem that is available as one of the default choices. (Don't worry - it will connect at 115 kbps, not 33.6 kbps).

3. Install the modem on any COM port that is available.

4. Once the modem is installed, select it and click on Properties. Under Advanced, add the following Extra Initialization command: AT+CRM=1 (without the quotes).

5. Go to Network Connections (or dial up networking) and create a new connection using the wizard.

Method:
As the size of hard drives increase, more people are using partitions to separate and store groups of files.
XP uses the C:\Program Files directory as the default base directory into which new programs are installed if your OS is installed in C: drive and so on. However, you can change the default installation drive and or directory by using a Registry hack.

So let's assume that your system directory is C: drive.

Run the Registry Editor (regedit) and go to

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion

Look for the value named ProgramFilesDir. by default,this value will be C:\Program Files. Edit the value to any valid drive or folder and XP will use that new location as the default installation directory for new programs.