I am using windows 7 64 bit and I have a gtx 670. Everything was fine until after I was messing with bios settings in regards to cpu overclocking. I did not do any over clocking just changed some auto settings to manual. Now when I put my computer to sleep and when I wake it up, it turns on fine but there is no dvi signal. I went back into bios and changed it back to default but still no luck. Now everytime I have to restart if I put to sleep.