i'm using the win2k at work and had a lot of issue with auto restart after a system upgrade.
it can not be deleted completely once it entered auto restart mode. 5 minute countdown will repeat again and again.
next time do this in REGEDIT then the computer will not reboot if a user is logged on.:
HKLM\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU
AUOptions 4
NoAutoRebootWithLoggedOnUsers 1
or, disable the auto update (either in "control panel/Automatic update" or in "Administrative Tools/.../services")if you could
all of those methods require the admin right.