[soul786]

My hard drive was nearly full -- so I wouldn't be shocked. I don't think I mentioned it but the sound from the fan coming from the power supply got more intense and higher pitched before shutting off, so I was thinking the power supply. But this could be completely wrong.

Would it be possible to try to disconnect the hard drive and run it connected to an external or something to test this? -- all I've got is my main hard drive and a couple externals. And if it is the hard drive is there any way to retrieve that data? Some stuff on there that I hadn't backed up yet

Easiest way to back up with only a harddrive will still need you to go to a store to pick up an external SATA harddrive dock. They plug into your usb port, and the harddrive from the computer slots in like its a toaster. Harddrive gets read just like a usb stick.