I installed Windows 8 and another monitor on my GeForce GT 240 video card. I have one monitor on a DVI and another monitor on VGA. Every couple of minutes the computer shuts down. It can be anywhere from one minute to one hour or maybe not at all. My power setting or set to NEVER on both monitor and Sleep. I'm wondering if it can be my Video card that is shutting down my computer. I know Video cards, and RAM or the 2 bad guys that can stop a computer cold. Or could it be something in Windows 8. Any suggestions?