Sudden appearance of multiple colored horizontal and verical lines?

OK, just woke computer up from "sleep," and everything is working fine. A few minutes later, all of a sudden, the monitor screen is filled with colored vertical and horizontal lines...and nothing is working nor is there anything else on the screen but the lines. Manually, shut down and rebooted. Opened with options on how to continue. I chose Normal Mode. Computer and screen now working as they should for the last hour. Any idea what happened and whether or not this is serious?

Well if they don't return it was probably just the video driver crashing from waking from sleep one too many times.

I can only sleep/wake my computer about 4 times before my audio driver fails and I need to do a full reboot.

I don't know if this will help, but I just checked the computer's temperature with Core Temp. As I don't know much about this stuff, I took a snapshot of Core Temp's read out while running 8 programs. BTW, when the lines first appeared (they haven't appeared again), I was only running my browser.




And here is, perhaps, a better indicator of what's going on inside my motherboard