I have just setup a new Windows 7 laptop for a user to replace their old XP one and whenever he goes to an intranet site using the FQDN, he gets prompted for credentials. If he enters his credentials, he can get to the site, but if he closes IE and reopens it, he is prompted again, even if he checks the box to remember his credentials. He can also get to the site right away if he doesn't add the domain extension to the end of it. It only happens with the FQDN.
If I login to his computer, I do not have this problem. He also doesn't have this problem on his old XP one. I checked his account and confirmed that everything is fine. I recreated his Windows profile and the issue remains. This occurs with IE9 and IE10.
We do have a proxy and I confirmed that our certificate was imported in IE. I also made sure that our domain was included in the AuthForwardServerList entry located in HKLM\SYSTEM\CurrentControlSet\Services\WebClient\Parameters.
Does anyone have any ideas why this is happening?