How to fix a messed up domain controllerJust get rid of it!
- Disconnect the DC from the network
- Run dcpromo /forceremoval
- From 2003, use NTDSUTIL to do a "metadata cleanup" to clean the DC out of your AD. (See below) If you have at least one Windows Server 2008 DC, then open Active Directory Users and Computers from a 2008 DC, find the bad DC, right-click and delete.
MS Article 216498 explains how to forcibly remove a domain controller account from AD using NTDSUTIL.