Here is a complete overview of all methods to try, I suggest you read through them to get an idea of what most likely applies to your situation, those advice can help you fix your computer issues very quickly.
To uninstall a program from Windows 7:
1. Navigate to the Windows start menu by clicking on the Windows logo (Start) button.
2. When the Start Menu opens, select "Control Panel".
3. Depending on your view options either click on "uninstall a program" or "program and features".
4. When the programs and features window opens select the program your want to uninstall from the list and click on the "Uninstall" button.
5. Confirm that you want to uninstall a program by clicking on the "Yes" button.
To uninstall a program from Windows XP:
1. Navigate to the Windows start menu by clicking on the "Start" button.
2. When the Start Menu opens select "Settings", then click on "Control Panel".
3. In the Control Panel window click on the "Add or Remove Programs".
4. In the "Add or Remove Programs" window select the program you want to uninstall and click in the "Change/Remove" button.