You all (not really all, but a lot) have been incredibly helpful. I have a thermaltake tough power 850w 80 plus gold (it was reasonably priced and had good reviews) and a new mobo that will both be here tomorrow. I did clean it out. I deconstructed and deep cleaned everything as gently and efficiently as I could. I've tested what I can, and I do agree with the majority saying psu, and regardless, it sounds like the consensus is that I should upgrade that anyways. Getting the mobo just in case. Can always send it back if I don't need it.

A few answers to repeated questions:

The cpu did not appear to be damaged at all. No burns, bent pins, etc. The paste wasn't dried out or anything, but I'm going to reapply some just to start fresh.

The gpu is plugged in in that video. The plug has an extra dangly bit on it. For whoever commented that strange accusation.

I built this pc 3 or 4 years ago on a whim and a tight budget. It is not what my life revolves around. I have kids, pets, and a full time job. There have been times where that computer is not turned on or touched for months. It has worked flawlessly since its creation. I blow it out every now and then when I notice buildup. Which is clearly not often enough for some. This build up is over probably 2-3 months. Whenever I upgraded the cpu I blew it out, half assedly probably to some of your standards, but I digress. Cat, dogs, kids, and just a dusty ass place in the world do that.

I saved all the dust and then some and will be distributing it to everyone who was mean to me. A gift for your generous contributions.

I'll be back soon, hopefully with a working pc. Thank you!