My computer started blue screening on startup last week. I took my GPU out, thinking it was the one damaged, and tried putting the GPU from my dad's computer. Sure enough, it worked just fine with it.
The problem is that after returning the GPU to its place, my father's computer wouldn't work. It starts but there is no video output whatsoever. We tried getting a third, functional GPU from my uncle and that was fine. We also tested father's GPU into uncle's computer and that was fine too. So the GPU works, the rest of the computer works, but paired together they give no video output. What the fuck is this?