Problem
Randomly, while using my computer, the monitor goes dark grey/almost black, or it goes white with faint grey vertical lines, or it goes blue with black vertical lines. It's as if the computer powers off. People tell me I sign out of Skype, Spotify stops playing when it happens, etc.
When I look at the tower, it doesn't seem like it's off at all. Nothing changes, fans are spinning, lights are on, etc. If you were only looking at the tower, you'd never know there was a problem
The only way I can get it to come back up is to push and hold the power button and turn it off, then back on
This never happens while I'm playing video games. I've done 5-6 hour sessions of League of Legends, and it doesn't do anything
When I'm just browsing the web, reading email, checking Reddit, etc, it happens all the time. It can happen multiple times in a session, it usually takes only about 5 minutes from the time I start browsing to when the computer crashes
This started happening after I moved to a new apartment (this has to be relevant somehow, it was not happening where I lived before)
There is nothing in the crash logs or event logs
System Specs
i5 2500k CPU
AMD Radeon 6800 GPU
Gigabyte z68a-d3h-b3 motherboard
WD VelociRaptor 1 TB HDD
Screenshots
Device manager
About screen
Things I have tried
I was getting a WMI Error in my event logs, but I fixed it using Microsoft's fix, KB 2545227
I was using Windows 8. I wiped the HDD and downgraded to Windows 7 64 bit
I took out the video card and used a can of air to totally clean out the video card, all fans, and the inside of the computer in general. I made sure all of the video card pins were fine, then reconnected it
I tried to update my motherboard BIOS, but anything I downloaded from Gigabyte was only for 32 bit machines, not 64. I don't even know how to tell what my motherboard BIOS is at right now
I am using a power strip, and anything else connected to it works just fine
If I re-seat the monitor cable while this is happening, nothing changes
Please, help me. I've been battling this for several weeks now, and it's so frustrating it makes me not even want to use the computer.
