Tonight I have encountered this problem for the second time. I leave my PC running, the screen goes black, once I move the mouse again the screen will light up again. The problem is that when I now move the mouse the screen stays black. If I simply turn the PC and/or power off the screen will not come back, the hard drive seems to be spinning, but the PC will not respond, even if I turn it off for say 10 minutes, nothing. The PC light on the switch stays red and the PC will not reboot. My theory is that either a) the PC is overheated (this is the second time this has happened and it worked again after about 1 hour), b) the video card has gone bad, or c) the hard drive is starting to fail. Can anyone confirm/deny either one of these scenarios or offer another explanation? Your input/help is greatly appreciated. Thanks!

Disable any power-off/standby options and hibernation. Then see if the problem recurrs.

"So won’t you give this man his wings
What a shame
To have to beg you to see
We’re not all the same
What a shame" - Shinedown

"Disable any power-off/standby options and hibernation" - does that mean unplug them? Since my screen stays black I have no vidual to see what is happening. I need to add that I have 2 lights on the front of my PC - green and red. The green light has stopped lighting, only the red one stays on, it does not flash, even after my 5 power off/power on's. Any ideas?

"does that mean unplug them". Unplug what? I'm talking about your Power settings that determine whether the monitor/hard drive will go into standy or shutoff after a period of time. I meant disable any of those settings.

Display
Screen Saver Tab
Power

And then click the Hibernation tab and disable that.

THEN see if you still have issues.

"So won’t you give this man his wings
What a shame
To have to beg you to see
We’re not all the same
What a shame" - Shinedown

Hey Jennifer, I think the OP is putting a bit of a red herring into his post regarding the monitor standby function. The real problem here is that he gets no display at all now, even from a cold boot.

This indicates a hardware failure and it could be as simple as the powersupply or it may be any of a number of other problems including but not limited to: Loose/dislodged cards/cables, Failed graphics card, faulty drives, bad ram.

Goin' Fishin' (Some day)

Jennifer/Richard, thanks for your help, much appreciated. As stated, my screen is black and I do not have any access to any power settings and can't make any changes. I had the PC checked out by the store that built it, they first thought it was the power supply (my guess too) but unfortunately is it a problem with the motherboard. He tried a 550W power supply, it booted up for 10 sec, then shut down. Seems like an error of power distribution or something similar. Since my ASA A7V8X-X motherboard is not produced anymore I am searching for one on E-Bay. Thanks for your help again!