If you are using Windows XP, follow the instructions below.
To change your default programs using Set Program Access and Defaults
Click Start, and then click Set Program Access and Defaults.
To specify the default programs for activities such as surfing the Internet and sending e-mail messages on your computer, do one of the following:
Select: Computer Manufacturer
Restore your settings to those selected by the manufacturer of your computer. This option is available only if the computer manufacturer installed Microsoft Windows XP Service Pack 1 on your computer and established settings for this feature.
Microsoft Windows
Use programs that are included with Windows as the defaults. Even though Microsoft programs will be used by default, you can still access all programs installed on your computer.
Non-Microsoft
Use non-Microsoft programs that are installed on your computer as the defaults. If you choose this option, access to the specified Microsoft Windows programs will be removed. You can, however, set up access to the programs at any time using Set Program Access and Defaults.
Custom
Use a combination of non-Microsoft and Microsoft Windows programs as the defaults. A custom configuration allows you to specify default programs for each activity. If you do not want a program to appear on the Start menu, the desktop, or other locations where programs typically appear, clear the Enable access to this program check box next to the program name.
Notes
The Custom option is always selected by default whenever you open Set Program Access and Defaults.
In the Custom section if you select Use my current..., the current default program for that category will continue to be used.
Software manufacturers determine how their products work with the Set Program Access and Defaults feature. Some non-Microsoft programs might continue to show icons on the Start menu and elsewhere even if you clear the Enable access to this program check box for that program.
You cannot specify different default programs for different users and you cannot remove access to programs for specific users. The options you set in Set Program Access and Defaults apply to all users on your computer.