Add/Remove Programs icon won't work

you cannot uninstall/re-install the add/remove feature by itself. One of the few times I have seen where this option misbehaves is when the system was infected with a worm/virus. Cant recall the name but came out July/Aug. last year.
Another way to force programs to uninstall is to go in the registry HKLM\Software/Microsoft/Windows/Currentversion/Uninstall and look for the program you want to uninstall. Yopu can delete it from here and should also delete the related program files.