What is your Operating System?
Does your question pertain to MSN Messenger (Instant Messenger), Windows Messenger (Instant Messenger) or Windows Messenger Service. They are all different animals and have different solutions. If you can clear this up, most likely someone can help.
Best of luck.
Glenn
HOW DO I PERMANENTLY DELETE IT FROM MY COMPUTER?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic