Dont know if this will help, but my MSN was signing in automaticly so I looked in help, and this is what it said, maybe you could try it but enable it to remmember your passwords????????
Go to User Accounts in the Windows XP Control Panel (to open Control Panel, click Start, and then click Control Panel).
On the Advanced tab, click Manage Passwords.
In Stored User Names and Passwords, click Passport.Net\*, and then click Remove.
This does not delete your Passport, but removes its connection with your computer.
Click Close, and then click OK.