After SP2 install I have found that Messenger does not sign in automatically after a cold bootup. Once I click on it and manually sign in it works fine thereafter until computer shutdown. Pre SP2 I didn't have to touch it at all to start it up.
I have searched forum and followed some ideas but no joy. Updated to 6.2 and disabled messenger 4.
Have you set it to start with windows and auto sign in when connected to net?,in the options part of msn,to do that you need to have your username and password saved in your net passport and messanger.