Take a look at Doug Knox's Website at this link for detailed instructions on
how to disable your Windows Messenger.
http://www.dougknox.com/xp/tips/xp_messenger_remove.htm

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.

Greetings Reggi,

To disable Windows Messenger, open up the main Windows Messenger window, click the Tools
menu, then Options, then Preferences, uncheck 'Run this program when Windows starts' and
click OK.
____________________________________________
Jonathan Kay
Microsoft MVP - Windows Messenger/MSN Messenger
Associate Expert
http://www.microsoft.com/windowsxp/expertzone/
Messenger Resources - http://messenger.jonathankay.com