When your DHCP server decides to stop working you’ve got a serious problem. When it’s a Windows server be prepared to jump through hoops trying to diagnose then fix the problem. After being led down many wrong garden paths, uncovering the nasty hidden depths of Active Directory I happened across this blog post. A single entry in the hosts file was all it had taken to bring down the network and removing it was all it took to restore service. Wow, if only I had found it sooner.
(For the purposes of Google):
Error: Attempt to configure DHCP Server failed with error code 0×80070005. Access is denied