Try using 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. If you can't find the application on the list with the installed applications, use Revo then click on the Advanced Uninstall and locate it then proceed with the uninstall operation.
After that, try running AdwCleaner to make sure that there are no leftover rogue registry keys or toolbars in your system.
