It may have become corrupted. Are you able to reinstall Works by any chance? If so do it, and use a repair option if offered. Then after a reboot the uninstall should work.
Alternatively try the Control Panel method in Safe Mode (reached by tapping F8 repeatedly while booting up).
Also, there is always CCleaner
which can often uninstall something that refuses to go.
Not sure what you mean by
Also I have software for other applications: how do I remove their Microsoft counterparts ?
Exactly what is it you refer to? Removing Windows Components can be dangerous, but some can be disabled or turned off I suppose. Please be more specific.