Check what's in the Event Viewer, set Windows 2000 to not reboot on error so you can read the Blue Screen Of Death (BSOD) and consider that without the latest patches, any number of WORMS can invade Windows 2000.
Your list omits the rest of the machine such as make/model number, power supply size and such.
Bob
I have a pentiumn 4 2.6 running windows 2000 pro. My problem is that the system shuts down and reboot with no warning. I watched for programs being used, time system was on, checked the event viewer, checked the temperture in cmost and took cover off computer for more venterlation. nothing seems out of place or acting up. Thanks for any help or feedback

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic