I'm having issues, too. After ~30 minutes of playing, the screen turns a solid color (I've had both black and blue) and neither the task manager or ctrl+alt+del work. The audio continues to play, but I have to restart my computer entirely. I'm using an i5 3570k and an HD 7870. I've tried both the latest stable drivers and the latest beta drivers, but neither sets seem to fix the issue. Of course, with the whole "you can't save while you're in a mission" thing, I've managed to lose about 75% of the progress made over the past few days.