Ok, so pc rebooted. On reboot, gets to the xp boot screen then flashes a quick blue screen error that is to fast for me to read, then just reboots. Ran memtest86 and had 3000 errors after a few hours. So grabbed a stick of 512 pc2700. The mobo supports pc1600/2100. Figured the 2700 would be fine as it would just run slower (2100). Still rebooting. I believe it is ok to run the faster mem slower like this, never had a problem before. Maybe another problem, like memory controller or something?