Have you tried to reinstall the game? If not, I suggest you do that first.
If none of the other possible solutions I provided worked, I'm afraid I have no more advice right out of my head. You should submit a support ticket if you haven't already.
Also, what's your PC hardware specs? Make sure you have at least the recommended specs to run the game.
“If you want to conquer fear, don't sit home and think about it. Go out and get busy.”
-Dale Carnegie
“Be who you are and say what you feel, because those who mind don't matter, and those who matter don't mind.”
-Bernard M. Baruch