Help!! Computer frozen at Hardware Monitor
So my computer today will not get past the hardware monitor screen. I recently unlocked the 4th core on my triple core processor, I didn't run any stress tests, just played bf3 and shogun 2 for hours and it seemed fine, no problems. But I thought maybe that was the problem so I set that back to run just 3x core and I still get the hardware monitor screen. I also just recently bought and installed a 6850, but have been playing on it for about the past week with no problems.
Can a loose video card cause this? I'm not sure what else the issue could be...
Help is much appreciated! Thanks!