A friend of mine signed on to MSN on my computer and their email address was forever etched in the memory of the login box. I didn't see anyway to get rid of the saved profiles inside MSN itself. Not the end of the world - but a little irritating nonetheless.
Here's what I did to start over again.
Go into the "(your user)/Library/Preferences/Microsoft" folder.
There's a file in that folder called "com.microsoft.Messenger.plist" that contains the saved profiles.
I suppose there's some way to delete out the profiles you don't want and keep the ones you do, but I just deleted the entire file, closed & restarted MSN and re-added my profile again.
Messenger recreates the file with the freshly added profile information and you can add the profiles you want to keep.
