Active Directory Restore

Hi, Can anyone help me with this?
I will get error message “cannot find domain controller or domain does not exist” everytime I open Active Directory Users/Domains & Trusts/ Sites & Services or Domain Controller Security Policy on my Win2000 Advanced Server.
My Root Domain was successfully installed & running perfectly with installed Service Pack 3.

I have tried to restore directory services for domain controllers, I even tried to restore Last Known Good Configuration profile, but still getting error message in windows. My Win2000 server is still under the same domain configuration settings when checking server’s properties.

How can I restore active directory services without formatting and reinstalling windows.

Thx for Helpingme.
Johann