At first: it's not audio, driver or RAM issue, I checked all the fixes on the net, but nothing works.
I was playing with Skyrim before, I had the same issue when I installed it and then I found something like "change windowed mod" or "change to lower res" - and it worked. It was an easy and simple step to handle the problem, but I can't remember what was this solution.
Yesterday I reinstalled the game and after the Bethesda logo it goes CTD with a small popup "Access steam community while playing. Press Shift+Tab...)", but it's enabled (Steam and game too) and shift+tab doesn't work. (It's the same with offline mode.) I tried mouse and vsync settings in the skyrimprefs.ini without success.
So, I know there is a simple fix for it, but I need help: what is it?