I don't know if this will work but it's worth a try and won't do any harm:
Go to: Start>Settings>Control Panel> Internet Options>Connections>Settings. Make sure your password is in there and applied.
Hope this might help
In outlook express, go to tool,accounts, click the mail tab, and highlight the mail account in question, if you have more than one, and select properties. Click on servers, and tick the box marked remember password, and enter your password.