I am a newbie to Windows 2003 Server but I setup a server 4 days ago. It runs, AD, DNS, DHCP. I setup 10 user accounts and everything has been working fine. Today I shut it down to plug it into a UPS and when I powered it up, it gave me the USERENV Event 1054 error. I researched it a little and ran the DCDIAG program but I dont get much to start on. The internet still works on all the clients, they just cant authenticate to the DC. I have a single label domain name so I saw the KB on that and went into the policy editor and told it to update to top-level domains ( ) this article. I didnt do the registry stuff, just method 2. I'm convinced that I have a DNS problem because the DC can't identify itself even though its on the same machine. I dont want to re-install everything and have to go rejoin the domain on 10 clients, is there anyway to find the problem ?