Either your computer has been on for a while (few days) and needs a reboot or something got corrupdated.
Uninstall/reinstall the game if a PC reboot doesn't solve this. Your save game shouldn't be effected by the uninstall.
You might have to update your video card drivers if problem still persists.
Those solutions don't work, with that he will only get upset and throw the game through the window.
My solution is easy and works great on all platforms

It's not a computer problem... it's the game
All the games till this one works great, this one doesn't, maybe the engine? let the larian stuff tell us whats going on here.