Typically, spontaneous reboots are caused by power problems. There are two real possibilities here - power supply is not giving adequate power to your motherboard, or your motherboard is not giving adequate power to your video card. If the spontaneous reboots only happen when you're playing 3D games, that should set some gears turning in your head. When a graphics card switches to "3D mode" it starts gobbling power like no one's business - Geforce cards have more transistors than your P3. Some motherboards in the past have been known to supply an inadequate amount of power to the AGP slot - when the card is asking for power, it can actually pull more than the motherboard can supply, and it'll reboot. Not much to do but replace the MB - the changes needed to prevent this are physical and can't be fixed with a BIOS update. The problem isn't with the card, but with the MB's implementation of AGP - the power requirements for AGP are well documented and the Geforce cards adhere to them.
As far as why it only happens in Win2000, I have to admit that that is weird. I have a similar system to yours, excepting the motherboard and sound card, running Win2000 without this problem. Win2000 is much more RAM intensive than win 98/me; perhaps that is joining forces with the above problem? Also, Win2000 has much different power management than 98/ME; perhaps this is also a factor.
[This message has been edited by Zoinksscoob (edited 20 August 2000).]
