We have a 2000 DC (SP4 - all current critical updates applied) that reboots during user logins in the morning. As far as we can tell, the reboots occur when multiple logins attempt to take place within a 5 - 10 minute period. Number of users is approximately 15; the DC is in a site of its own; the DC holds the roaming profiles for the users, as well as the printers.
After the server reboots, we have the users login one at a time with no problems.
This server did have an issue with rebooting itself on occasion before we discovered there was a problem with the system board - the board was replaced a couple of months ago and the problem was resolved - until last week when we noticed the login reboot problem. In other words, we're really not suspecting the replacement board as the culprit this time due to the fact the reboots occur during logins only.
We've inspected the logs, and nothing appears to be a clear indicator as to the problem......we are going to swap this board out today or tomorrow to at least eliminate it as the problem once again.......any input would be greatly appreciated on this one.