Manually Uninstalling a Program
Warning: Always make a backup copy of the registry, before Editing !
Make a copy by selecting: Registry/Export Registry, then save it on your Desktop.
Click the Start button and select Run. Type in: regedit within the run(command) box.
When the regedit window appears, expand the tree(click on the + to the left of a key or folder) beginning at HKEY LOCAL, until you find the Uninstall Folder.
This is the full path: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows \CurrentVersion\Uninstall.
Expand the Uninstall folder tree(*1) and all the programs currently installed will each have a folder. Click on the folder(*2) you want to uninstall (3Dfx in the example below), and in the box on the right you will see, two strings: DisplayName and UninstallString(*3).
Double click UninstallString, and a box(*4) will appear with the uninstall string(*5) highlighted within it. You can right click on the highlighted entry & select copy. Close Regedit.
Select the Start button, then click run. Right click in the run(command) box and paste the the uninstall string inside, click ok and it will uninstall the program.