I have the same random reboots running Windows 2000 Server with a Tyan dual cpu motherboard and two AMD 1800 cpus and 1GB of RAM. The ram was 1x512MB and 2x256MB All RAM are DDR2100. When I try to change the memory configuration(remove the 512MB module) I get a blue screen when windows begins to boot. The only configuration of the Ram that allowed me to boot was the original, or just a single 256MB in slot 0. I replaced all RAM chips-same problem, I replaced the Power Supply-same problem, I replaced the Video Card-same problem, I replaced the motherboard-same problem. The only things left to replace are the cpu's, the NIC, and the Raid-Controller(It's an Adaptec 10). I even removed the antivirus software. Now the only thing on the machine is Windows and ARCServe. Any Ideas? Help! pryan@bodkin.com

You said the only way it works is with the original memory configuration, so why are you messing with the other parts? If it's the memory, make sure you have the correct speed. Also, check and see if your board requires you to upgrade it with specific modules such as 2 128s instead of a single 256....