Hey, i just bought a new MB, when i installed it every thing went good, started it np (no harddrives or discdrives in). That day i was going out so i did not have time to check it more, but the next day (today) i fastend the screws to the cpufan correctly (i did not have the original so i just took 4 screws) then i plug in the hdd and start. The fan starts goes normally for 2-3 sec then "accelarate" like **** and the computer dies, it restarts itself after a half second or so. So i remove the hdd: nothing I disconnect the computer from the power src for a fex seconds then start it: it starts like normal. But sometimes it wont work even if i disconnet the power and alll that I can't start with vga cable in. What i have tried. I tested different RAMS, powersupplies, hdd , cd and cables. I checked the cpu, and it was a little bit of thermal paste on it so i carefully rubbed it off. i started the computer and when it was in bios i plugged in the hdds and cd's and started to install xp but i got a blue screen and error pci.sys address f748e0bf. I cheched all the cartridges. I unplugged the heatsink. I removed the MB and placed it on a shoe box. Set up Msi g31tm-p21 p4 3.2 i think might be 2.8 3.0 or around that. 2x ddr2 533 1 gb pc4200 rams a 380w psu Radeon hd 5450, not plugged in now. 2X 120 g seagate ides hdd That should be it. Thanks alot, hope my swedish english wont be a problem.