Hello, I just recently bought the game through steam and I'm also having it crash fairly often. It seems pretty random to me. It can be just sitting still with no input from me and crash. If I pause it and go away for a while it can crash while paused. It also happens while playing... seems to be mostly while in the view where you can see all of your buildings and the landscape... possibly other views also.
I updated to the latest 531.18 nvidia drivers and it didn't fix it. I don't have any other programs open. Just steam and antivirus.
Besides this, the game seems pretty fun so far. Hope it's an easy fix!