The issue: At seemingly random times, my system will go to sleep. When this happens...
1) video to the monitor haults (so the monitor goes to sleep)
2) the power light changes from GREEN to YELLOW, and
3) the video card fan revs up to max speed (and sound)
4) the system doesn't respond to any keystrokes
When this happened in the past, the system would come back on it's own after several minutes. It also used to ONLY happen while I played a game. It also used to be a rare occurance.
Now, however, this happens almost everytime I use my PC. It has also started happening while I'm merely reading e-mail. The only way to recover the PC now is to force a cold shut down.
My initial thoughts were the video card "stalling" from working too hard (because it happened during gamming and the video fan speed increase). Now I am starting to wonder if it may be hard drive related.
So I ask the community...what do you think is the cause?
I tried Memtest. I ran 2 instances of it, each on 1000MB of RAM (I have 3 total). Both instances got to around 120% without any errors...then the system locked up and went to sleep.
So, the tests didn't find any errors, but the problem occured during the tests. What that means, I have no idea.
I spent the evening backing up files. It took all evening because the PC locked up and went to sleep about 10 times. Luckily I was able to properly shut it down when I was done; I think that's the first time it shut down normally (without me holding the power button) in a week or more.
Regardless....still at a loss of a solution, but thanks for the help so far.