Hi,
To Prevent Windows Messenger from Running on a Windows XP-Based Computer
http://support.microsoft.com/default.aspx?scid=kb;en-us;302089&Product=WinMsgr
When you do this your Windows Messenger won't show up in your taskbar
anymore
However if you want to completely remove/uninstall Windows Messenger from
Windows XP can be found at this website made by Jonathan Kay.
http://messenger.jonathankay.com/problem.aspx?ID=7
Follow the steps and the pictures that the website has and you shouldn't
have anymore problems. Uninstalling Windows Messenger can disable some of
the messenger features such as Whiteboard Sharing, and others on MSN
Messenger if you're using that.

Signature
Gary Tsang
Microsoft MVP - Windows XP Shell/User
http://www.microsoft.com/mvp
>I receive an error message "you have been signed in to
> Messenger on another computer." I have no other computer,
[quoted text clipped - 6 lines]
> on another computer. Clich here to sign in ... then the
> pop up ... You have been signbed out of .Net Messenger