What do you do if a Domain Controller dies and cannot be revived? Just deleting it from Active Directory won’t do it.
There is only one thing you can do, remove it forcibly.
Petri has an article that can help you do this.
When you try to remove a domain controller from your Active Directory domain by using Dcpromo.exe and fail, or when you began to promote a member server to be a Domain Controller and failed (the reasons for your failure are not important for the scope of this article), you will be left with remains of the DCs object in the Active Directory. As part of a successful demotion process, the Dcpromo wizard removes the configuration data for the domain controller from Active Directory, but as noted above, a failed Dcpromo attempt might leave these objects in place.