Hi This is how I got to this state: My room was really cold from having the window open and sub 0C air rushing in. The PC case temp was 12 degrees cooler than normal. I decided to try a bigger Radeon X850XT overclock than usual since there was so much natural cooling available. I chose 600/600 for GPU/RAM and started 3DMark06. I left before the bench finished. I returned 20 minutes later to see the PC rebooting to Windows XP Pro login. I login. 5 seconds later : BSOD "Machine Check Exception - 0x9. Sometimes during a boot it gets the BSOD even before login. I'm able to run Knoppix withour problems. I could run Memtest on 2 GB ram (in DFI Ultra-D Lanparty BIOS). My first question is: is my Radeon still set to 600/600, which is maybe too high even for a very cold room? If so, what can I do to reset it back to defaults if XP isn't bootable? I can't reach Safe Mode either because of the BSOD. My boot disk is a mirrored Sata raid disk (nForce 4). I was hoping there would be a floppy-based version of AtiTool I could use to check things out or reset the Radeon's clocks.