hi
We had 4 DC.
The forth DC (DC04) was many time shutdown.
The Tombstonne life time past
He we are the links to solve the problem
http://www.petri.co.il/forcibly_removing_active_directoy_from_dc.htm
http://support.microsoft.com/kb/555846/en-us
http://support.microsoft.com/kb/216498
http://www.petri.co.il/delete_failed_dcs_from_ad.htm
http://technet.microsoft.com/en-us/library/cc757610(WS.10).aspx
http://www.eggheadcafe.com/software/aspnet/29759019/dc-past-tombstone-lifetim.aspx
Resume:
dcpromo /forceremoval
Clena with the AD tools any entry in DNS and AD
sAnTos