You think you have uninstalled windows messenger, but you haven't!
If you'd like Windows Messenger to show up in the list of programs you can add and remove from Windows, navigate to C:\WINDOWS\inf (substituting the correct drive letter for your version of Windows) and open sysoc.inf (see the previous tip for more information about this file). You'll see a line that reads:
msmsgs=msgrocm.dll,OcEntry,msmsgs.inf,hide,7
Change this to the following and Windows Messenger will appear in Add or Remove Programs, then Add/Remove Windows Components, then , and you can remove it for good:
msmsgs=msgrocm.dll,OcEntry,msmsgs.inf,7