BSOD's after I upgraded Windows 7 to Windows 8 Pro

Hey!

So like the title already tells you I started to get BSOD's after I upgraded windows 7 to windows 8 pro two weeks ago. I have been trying to figure it out myself I reinstalled windows 8 twice, updated all drivers i could think of and reinstalled graphics drivers but nothing worked. now i really need your help to identify the problem driver/hardware.

Some observations: sometimes it just freezes and sometimes BSOD is corrupted(blue screen with white lines everywhere ). BSOD usually happens while playing.

I hope you can help me

Thanks!

Run driver verifier
Use memtest from hcidesign.com
Replace gpu
Go back to windows 7

Bugcheck 139.
Virus?

Well according to windows defender i have virus free system. Lets see if I can lend gpu somewhere and if that doesn't work I'm gonna run verifier and memtest.