So it's been over a month since I've had a working PC. It's been exhausting, but I finally figured out and rectified the problem... more or less. For a while I thought it was the power supply, then I did some troubleshooting and thought it was the motherboard, some more troubleshooting, and finally I reach the end of the shrubbery maze; my primary hard drive was toast. This sucks, as a lot of my important client work was on this drive. Normally I save back-ups of everything to an external drive, but I got a bit lazy in my hastiness to meet deadlines and made the mistake of saving some of my work to the desktop.
I replaced the hard drive with a fresh install of Windows, and I have been working off of it since. There's still a glimmer of hope for my old hard drive, but it's a matter of money, and I'm woefully short.
I'll be pulling a few all-nighters in the coming weeks to catch up on the work I've missed. More to come.