Hello,
Was your MSN Messenger installed or updated as part of the new MSN Explorer 10 ?
Also has it been working properly until recently, and if so what changed just before you noticed it not workin - new windows update, new program installed, new driver updated?
I'm assumming you are using Win-XP, since Windows-7 doesn't have messenger, you have to download Live Messenger. Go to All Programs, find Windows messenger (part of Win-XP) and try that to see if it works OK.