hd4000 crashing

Hi, i recently bough a brand new computer (each part separate) but it keeps crashing when i play or run any fullscreen app like youtube, 3d or gaming, i need to hard reset my computer by pressing the power button for like 5 seconds to be able to use it again.

I ran some tests on memtest and prime95 and no errors showed up.

i have a 550w psu that used to hold a gtx260 before the gpu died, now i'm using the hd4000

here is my config

DXDIAG: http://pastebin.com/4RXxrEis

my bios is updated.

thanks!