Greetings Freddy,
Assuming you just use MSN Messenger, you can simply disable Windows Messenger. To do so,
open it up (click Start, then Run, type "msmsgs" and click OK), click Tools, Options,
Preferences tab and uncheck 'Run this Program when Windows starts' or 'Run Windows Messenger
when Windows starts' (depending on version) as well as 'Allow this program to run in the
background' or 'Allow Windows Messenger to run in the background' (depending on version).
This won't remove Windows Messenger, so features like Remote Assistance, Whiteboard and
Application Sharing will continue to work, but it will let it stay out of your way.
Since it only happens occasionally, it could be that it's starting with Outlook Express
(assuming you also use Outlook Express). To stop this, close Outlook Express, then download
and run this .reg file:
http://messenger.jonathankay.com/downloads/stopmessenger_oe.reg
____________________________________________
Jonathan Kay
Microsoft MVP - Windows Messenger/MSN Messenger
Associate Expert
http://www.microsoft.com/windowsxp/expertzone/
Messenger Resources -
http://messenger.jonathankay.com