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.
Once the process is complete, run Revo again and look for the app to remove leftovers.
After that, try running AdwCleaner to make sure that there are no leftover rogue registry keys or toolbars in your system.
