15 R2, graphics crash on most 3d games

My computer worked fine until it broke and I sent it to be repaired, It can now not run any 3d game unless it's running off of the intel graphics. On afterburner if I look at the temperature graph the gpu goes from regular temps (60-70) to 0 and back up. I've tried new drivers, resetting my pc, clean boot, upgrading bios. None of these have worked. And Every game Im playing meets the system requirements.

Alienware 15 R2

Geforce gtx 980m (used to be 970m before repairs by dell)

Intel i7 6820hk (also new I think it used to be 6700hq)

16gb ram