Power User cannot open website in IE5.5

Win2000 Pro…I have a Power User who cannot get access to a website using IE5.5. As an admin, I can get right in. The security settings are exactly the same in IE for both profiles. The website is a university online class. The user had access to it with Win98 at home, upgraded to XP and now has no access. Also no access with W2K. I’m pulling my hair out! Any ideas?

Thx!