If uninstall and reinstall of MSN software doesn't cure it, then it's time to call their tech support. MSN doesn't publish or share their support knowledge base so such things are much like AOL.
You get to call them.
I have Windows XP and MSN will not boot to online status. Every other program that I have will go on line for me, Yahoo, Road Runner. I can get Internet Explorer, but MSN will not allow me to receive e-mails or updates.