Well, two initial thoughts:
1) The HDMI mini adapter has apparently gotten permanently stuck/fused into the slot on my GPU. I hope I didn't damage anything while trying and failing to remove it >,<
2) The amount of dust in the computer is not as bad as I thought it would be, though there is still a lot
Took a photo of the interior of the computer before I started working
@Zauberin She's a bit dirty!