Windows 2k Professional hates putting machines on the domain when you are logged on as a domain administrator (using cashed information) log on as local administrator and then try again.
I have had this problem when imaging PCs, the new image says that the PC is on the domain but when you try to explore the domain the PC cant see it. In this case I have taken the PC off the domain, put it on a workgroup, reboot, logon as local administrator and then rejoin it to the domain.
If you are using Win2k Professional on a Windows NT domain then you need to ensure that the WINS settings are correct, as this will also stop it joining the domain.
The RUN, CMD,
ipconfig /release
and then
ipconfig /renew
fixes a lot of domain issues.
Also check that your computer is seeing the right network card.
Have you checked the cable and then right back to the hub/switch box? Can you connect another PC to this network point and it works, maybe its not plugged in your server room?
If you are working on an Windows 2000 platform for your domain. Windows 2000 is very particular with its SIDs (the user name is linked to a long SID number which was okay to muck about with on WinNT platform but on Windows 2000 it basically wont be messed about with, it does not like change). I am sure one of the other members can explain this better, we are only just going over to Win2K domain but I remember this bit from the course I attended.