I have been tinkering with a SBS 2003 box that has been restored from backup. One of the annoying things I have come up against was that it wouldn't reboot quickly enough and a "service or hardware" failed to start popup would be there when it finally arrived back at the login dialog

Looking at the event log I saw this error:

Event Type: Error
Event Source: Service Control Manager
Event Category: None
Event ID: 7022
Date: 2/05/2008
Time: 1:36:41 PM
User: N/A
Computer: MYDC-01
Description:
The Kerberos Key Distribution Center service hung on starting.

After a fair bit of trial and error I think I have traced it to the custom self signed ssl cert that I installed.

It appears if you use the self signed approach and don't supply the root CA and trust it. A reboot then takes about 15 minutes or more to complete and the above error occurs in the event log.