Crashing and I'm wondering if it's caused by textures

[Filizitas]

Easy one, but only people with bad pcs like me know that stuff instantly
Yes its your memory/RAM. The textures fill alot of it and the vram too. Once the ram is full the system switches to a special system to manage the memory.

This means when you move you camera a bit its starts throwing out old crap in loading stuff completly new in. Do that a few times and the system starts lagging.
You will get screen freezing and randomly the game will send you to the desktop.

You cant change that.

Play with medium and leave it there, or you buy yourself some new hardware... but thats not needed since you actually said u can play the game with lower textures.