When attempting to active a Windows 2008 server with slmgr, you get the following error message:
Solution
Both errors (0xC0000022) are “Access Denied” errors.
Make sure the service is running as a “Network Service” account and that you have administrative access (local admin) especially if you try to activate a remote machine.
If you changed the account the service is running with, restart the service and it should be fixed.