Removing a DC in Active Directory

My network is running Active Directory in Mixed Mode. I just had one of my Domain Controlers fail horribly and I cannot get it back online. I rebuilt the server and restored the data from backup. I gave the rebuilt server a new name and it is working fine. My problem is I cannot get the old server name (object) out of AD. Since I rebuilt the server, I cannot “demote” the old server that crashed. I am worried because when AD replicates, I don’t want it to fail by trying ot replicate with this server that no longer exists. Can someone help me get this server out of AD..