Can you tell me your procedure of removing a DC ? I'm pretty sure there can be a situation when its not possible to even power on a DC - broken mobo for example - and every serious admin should have a ready plan for that scenario.
I'm talking about an environment where the highest ver of Win Server is 2008 R2.
Here is what I would do:
1. change IP settings of other DC(s) so they don't point to that failed DC for DNS.
2. Seize roles if it was FSMO role holder
3. clear DNS of any IP addresses of failed DC
4. remove DC object from users and computers
5. Set a different DC as a time server if necessary.
Is there anything you would change, skip, add ?
Please let me know. Unfortunately, as always - I need to add that I'm only interested in first hand experience.