first enable viewing of all files including operating system files.
Navigate to C:/windows/inf
Open sysoc.inf
find msmsgs=msgrocm.dll,OcEntry,msmsgs.inf,hide,7 in the file and take out the word hide so the line would look like msmsgs=msgrocm.dll,OcEntry,msmsgs.inf,,7
Close the file and save it
Now go to the Add and remove programs applet in the control panel and you will be able to uninstall windows messenger.
Make sure to click on the add remove windows components button.
Note: You will be able to uninstall other unneeded programs by removing hide from the sysoc.inf file as well.