Computer freezes and screen grays out or gets patchy pixels or lines

It's happened three times in the past 4 days. The computer just freezes and the monitor grays out of gets odd looking streaks or pixels in it. Pressing the ESC, CTRL-ALT-DEL or the power off button has no effect. I have to actually pull the plug to turn it off. I ran MSE, MalwateBytes and SuperAntiSpyware scans. Nothing found. What is going on here?

Attached is a Speccy scan to show what hardware I have.

 

First, try starting the PC in Safe Mode (keep tapping "F8" as soon as you turn the PC on). This will load Windows with only basic drivers and very low video resolution.

Disable any "sleep", "hibernate" or "turn off hard drive" options in CONTROL PANEL > POWER OPTIONS and leave the PC on for several hours or overnight.

If the problem repeats in Safe Mode, it points more to a hardware issue. If it does not, I'm leaning towards a corrupted video driver.

Post back with what happens in Safe Mode. Thanks.

 

I will when it happens again. Thanks for the suggestions.