Using: Winxp 32 and 64bit pro Cpu: Amd s939 3500 newcastle processor Ram: CMX512-3000xl from corsair MB: Asus A8N- Sli Deluxe Rev. A3 HDD: 1 WD raptor 74gb sata, 1 WD Ide 200Gb, 1 Seagate Sata 200gb sata. Cooling: Watercooling from Asetek, 3 fan raditor, cpu, gpu, chipset waterblocks. Vgacard: Sapphire Ati radeon 800xl Problem: Windows suddenly starts to reboot, and restart evey time windows tries to boot. Windows reinstallation (fresh copy with formated drive) BSOD anywhere under windows installation. I used bios 1009 for a long while, and it worked fine until lataly... Just a week ago windows bsod, everytime I logged in. I formated partition and tried reinstallwindows, but it bsod everytime. Used ez flash utility built into the bios at bootup, and flashed bios back to original bios (Strange symptoms: two squares where not updated under the update procedure. Recieved a cmos checksum error message after the first boot, but not after entering bios,and the saving and restart. In bios settings from the bios I was using before were still there, and not defaulted like it usually does after bios upgrade. Also bios freezes up when trying to enter cpu vs ram speedvalues, and cpu multiplicator values in bios). After doing this I was able to install Windows with a fresh copy, and running windows without a problem, and I still do. Using Asus update to update the bios, I recieve a message from the server that it cannot find a proper bios for me, meaning It doesnt recognize the motherboard. I cleareded cmos with pin and battery (not everything was set default, it seemed) Then I Updated bios to bios 1014 (recommended chipset drivers installed), and same problem came back, I flashed back to original again and it worked again. I even tried with bios, 1011, 1015 without success. I have also tried to update bios from windows, but there is no change in symptoms. Checked if different hdd's and psu did make any difference, well it didn’t. I even deassembled the whole system, and cleaned all parts and put them back together. Still no difference. Idle Temperatures is: Cpu 27, chipset 25, vga 30. The ram passed all memtests in ultimate boot cd, so I don't think its the ram? Is the bioschip damaged? Why does the system work with original bios and not any other?