Windows 7 Lock-Up After Idle?

The issues come when I leave the PC overnight, idling, with the monitor physically turned off (I use the power button). When I come back in the morning and turn the monitor back on, there is a black screen and the PC won't wake.I have left the computer idling during the day for many hours with the monitor being in standby (PC turns it off, not me).Interestingly, when the PC "hangs" after the night I can still access stuff over the network, and play some videos on my TV which is DLNA-ed to it. Logs do not show any issues, in fact there is some logging going on all night meaning the PC isn't totally dead. However, I try plugging some USB devices in and out, but it doesn't make that USB recognition noise.

Things I have tried:

- playing around with power settings, ie. disabling USB turn-off, disabling ULPS on my vid card (ultra-low-power-savings mode), changing the screen turn-off times, turning sleep and hybernate/hybrid off

- note it is NOT a taskbar auto-hide issue. If you are having crashing problems after idling (still able to access PC for 10s of seconds before it freezes), be sure to check out information on the auto-hide of the taskbar

Other info:

- I run utorrent overnight As a test, I turned my monitor off (physically) during the day, and came back to a "hung" system. I think this may be the root of the issue but it's still driving me up a wall because it's such a weird problem. I have to keep trouble shooting the issue to be certain. Furthermore, my main concern, and the reason for writing this post, is that I want to make sure this is not some hardware issue that is later going to progressively get worse. To me it doesn't seem like a hardware thing, but maybe there are some experts out there who can shed some light.