Ok, I have a media server here with an interesting problem. Here are some specs: AMD dual core 600 watt power supply, bought new 2 years old. Older server motherboard no problems before, but who knows. Nvidia 9500 graphics card 4 gb of ram installed, only addresses 3.5 gb Windows 7 pro 32bit The computer is totally powering down while leaving the bios and before the OS begins its own start-up. Yesterday some friends were watching a dvd and the pc blue screened. That was the first time we have had a blue screen since the computer was assembled over a year ago. At first I thought perhaps we had a bad hard disk, but that would not explain the total powering down of the pc. At worst, it should just fail to start the OS. I used a linux boot disk to run a memtest and that turned out fine. The real trouble came when I instructed linux to boot from the disk but not install. The computer shut down at the exact same moment as the W7 OS when I tried to boot using the Linux OS. To me, this rules out the bad hard disk theory and only leaves possible 1. Bad power supply- I find this unlikely as it has no problem running while in bios and while running the memtest. The PC is also failing at the exact same moment when operating from two different boot sources. 2. Bad motherboard - At the moment this is the only I can't rule out although the bios operated fine when I checked its settings. 3. Something is shorting out. Its possible that this is the cause and I will try removing the peripherals and reinstalling them to see if this avoids the issue. That will probably be my next course of action. Does anyone have any input? Ever had this problem before? Remember the PC is shutting down at the moment that the OS (both linux and W7) attempts to start up from two different boot locations, a hard disk and a DVD drive.