[PC] Game hard crashes after 20-30 mins gameplay

It was to be feared that this would happen. 
The problem is that we slowly running out of options here because we can't pinpoint a specific problem. 

The game is running for a good amount of time, so it is most probably not a game related or at least not only game related problem.
Hard crashes like this are almost always at least partly hardware/driver related. 
The fact that you don't get a BSOD is also pointing in this direction. 

What kind of power supply do you use? (brand and model.)

Lets have one addition test:

1. Create a new Windows user account (Administrator) don't use local special characters, use only  Characters from the ASCII table
2. Reboot > Log in to the new user account.
3. Test the game.