If the built-in uninstaller will not work, then you can use other applications that were developed exactly for these situations: download and install 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, including registry keys and obsolete files.
After that, try running AdwCleaner to make sure that there are no leftover rogue registry keys or toolbars in your system.