Windows Live Messenger Uninstaller allows you to remove a broken Windows Live Messenger installation. It uses only the windows installer (msiexec.exe) to do the job combined with the CLSID of the installation that uniquely identifies the WLM version.
The tool is very simple to use. If it finds an installation it will give you the uninstall command that you can use to manually remove it. You can also press RUN and it will run the command automatically for you.
Download Windows Live Messenger Uninstaller