I’ve had this on a few windows 2003 machines, where the “DHCP client” service refuses to start and prompts with an access denied window.
Unsure of the cause at this point (it may be a security patch), but here is the fix…
Give the local “network service” account full rights to the following registry key;
Now try starting the service, should work. In some cases you may also need to add the rights to the following key..