System always hang with Win2k

[CP]

I have Win2k running and never shut it down. So screen saver will start itself after 10 minutes. But everything I came back from school my pc just hang. I have GF3, 256MB PC133 and Duron processor. Also have SP2 installed, Dx8.1, and with latest driver for video (Detonator XP) and sound (SBLive MP3+).

Any hint?

Thanks
CP