Reading your other post:
[B]roken.[Hearts]'s reply to My msn keeps signing me out, I get a feeling you have either a very bad connection (note that a connection can be lost even if the connection icon doesn't show anything out of the ordinary) or your internet settings are seriously screwed up...
this might be a very long shot but start by disabling AVG (it recent update or something caused problems in Messenger for a lot of people) and reset the settings in your firewall (that is: remove all the blocked and allowed programs). Then enable stuff again one by one after you notice things are better (if things are better of course).
/ 
