I have an ATI Radeon X600 Pro video card in my PC. I have had it for ~6 mos. I am experiencing random crashes that always begin with the monitor shutting off while the sound continues for a short while. After a short interval the PC will reboot. Most recently the monitor's shutting off was also accompanied by a crackling static sound from the speakers. The crashes are happening more and more often. I have gone completely through my system several times and am convinced the problem is not caused by malware of any kind. I finally became convinced this is probably a video card problem when I installed a fairly demanding flight sim and the incessant crashes made it dificult to run the sim. A question to a sim forum brought answers blaming the video card. So, my question: How do I determine that the card is the cause of the trouble and not something else? Thx for any direction on this.