BSOD: GEEK SQUAD said they fixed it! LIES

All sorts of programs are crashing.

I go to game and it crashes

Computer freezes only way to get it back is to turn it off.

Mobo is a msi z390 a pro
Ram gskill trident z rgb 3000mhz 16gb
Hard drive 1tb western digital 1 year old
1tb ssd Samsung
Psu Corsair rm 850w
CPU i5 8600k (not overclocked)
GPU evga gtx 1080 sc

PLZ help I'm at my wits end here!