Computer Help Please! My computer keeps crashing after installing new GPU.

[Callinon]

That sounds like you're losing a graphics card. The description here sounds like a hardware fault of some kind, not a driver problem. Also you were right to scoff at the "switch to Windows 10" suggestion from AMD. That isn't going to help you. I mean you should do it if you can because 8.1 is a pile and 10 is not, but that's beside the point.

You can check temps on your CPU and GPU with a utility like SpeedFan. If your CPU were overheating the entire computer would shut down. If your GPU is overheating it could manifest itself like this. It's worth checking to see what kind of temps you're getting when the game is running. But honestly, it sounds like you've just got a dying card.

NB: Mmm also, please report computer temperatures in Celsius. It's a far more standard scale even in the US when measuring something like this. Easier to tell at a glance if something's up without having to convert first. As a rule a computer will shut itself down over 100C and anything over 90C should be concerning.