Personally, I'd just replace it. Replacement of an optical drive only takes a few minutes and you can get a DL DVD burner with lightscribe for $25 dollars shipped. Use this as an excuse to get the...

This is usually a defective hard drive, so it's odd that it would come back clean. I would suggest:
1. open the case and re-seat all the cables.
2. reset your BIOS manually by unplugging the system...

I suspect that the consistently high temperatures of your GPU have just worn it out.

I think it's a video card issue of one form or another. We might be getting blinded by your high temperature, and overlooking a more fundamental issue. Maybe there's a defective card that's failing...

That is very hot, there's no surprise that it's failing. Obviously an after-market cooler would help, but the stock should work as long as you're not over-clocking. If you're hitting temperatures...

If it's new hardware you should almost hope it's a hardware problem. If there's some kind of incompatability with the OS you'll have to wait for a fix. If it's the hardware you can still exchange it...

It could be the PSU, You should have about 100W of cushion on it, but if it's failing it might shut down your system when under heavy load, since that video card uses a lot of power.

The other...