I pulled stick two, re-seated stick one, and it was fine. Added 2nd one back in, solid beep. Pulled stick one, moved stick two to slot one and it was fine. Added stick one to slot two, solid beep. Back to just stick one, reset bios defaults, try both sticks, solid beep. I am using two identical IGb sticks of Kingston Value RAM (KVR667D2N5/1G). The mobo is an Asus P5R8L, with an AwardBIOS. I flashed it to v0801 from the Asus site a few months ago. I also noticed that the FSB was only 200 MHz, not 800 MHz, but the BIOS sucessfully identified the CPU. How does a DIMM go bad durring normal operation? I mean, the system was on and running when the first solid beep started, and I was asleep so it was idling. The system is behind an APU UPS, wich repoted no problems around the time it happened.