+1 to the standard Windows uninstall if available
Sometimes the uninstall database is corrupted, and often reinstalling the application (or repairing if that is an option) will put it into a state that the uninstall will work. Sometimes uninstall will fail due to running components, so running the Windows uninstall from safe mode will often help. Applications like
Revo Uninstaller Free will sometimes work when standard methods fail. And of course you should check with the application developer site to see if they offer an uninstaller specific to the application. Your situation may be complicated by the possibility of shared components between the full program and the lite version, but if uninstalling one kills the other, then you can just reinstall the one you want to keep.