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.
After that, try running AdwCleaner to make sure that there are no leftover rogue registry keys or toolbars in your system.
After you run all these things, run Revo Uninstaller again and locate the software in the list. If you find it there, proceed to its removal once more and it should be gone forever.