I FIGURED OUT WHAT'S WRONG WITH MY PC!!!

i have a bad pci-e slot. basically i swapped the 290X back in being like well, let's try this again, and i noticed something. i put the card in, connected it and it was working. i pushed the computer back in it's place, and it froze, rebooted and then black screen. i couldn't get it to post after that.

so, i pulled it back out, opened it up and pushed the card down into the slot and it worked again. pushed the computer back in it's original spot under the desk and black screen again. i then reached around it without moving it, pushed the card down and now it's working.

so, i'm gonna see how it runs like this without touching it, if it continues freezing i'll try a different pci-e slot.