Manually remove Active Directory

DC1 no longer is showing DC2 as part of active directoy, because I had to restore DC1 from an old backup. DC1 is also the DNS.

dc promo will not allow me to demote DC2 I keep getting the error:

The DSA object is not found

Is there a way tomanually remove Active Directory from DC2? If not is there a way to Make Active Directory see DC2 as part of the active directory?

Thanks,

Preston