Active Directory Headache in w2k server.

Get the following error when i try to open a AD utility such as Users and computers.
Naming information could not be located because : the network path was not found.
I think the problem might be to do with dns, i’ve seen someone suggest removing isp dns and enabling forwarders for the same problem. but has no effect, nor does running secedit to restore db defaults, or restoring system state b’up to known working copy. i hav basically tried every thing i can think of! bar reinstalling the whole dam thing! srv pack 4 loaded too.
We had a virus, and some files might be lost or corrupted.
please help. i’m desperate!!!