Larian Studios Forums Divinity II The Dragon Knight Saga / Flames of Vengeance (English) Technical problems pc crashes and restarts. windows 7(64-bit)

I bought the humble bundle and i'm really enjoying divinity II. but there is a problem, i'm playing this game for like a good hour or 2 but then my pc crashes and restarts without any visual clue on how it happens.

I'm running the game on the highest settings (fps cap at 60) without any problems (except the crashing that is).
my system: 16 GB ram
GTX 770
Sabertooth Z87 motherboard
i7-4770K cpu

thanks in advance

edit: I also have 2 screens