If you can't uninstall the program using its uninstaller or Add or Remove Programs Feature (Control Panel > Uninstall a program), I recommend you use Revo Uninstaller. Even if it can't uninstall the application normally, it will force it to uninstall by wiping out all traces of its presence from the system. After that, run a registry cleaner from Software Informer database to make sure that there are no leftover registry keys or toolbars in your system.
