Turn off your Screensaver 
I had problems with getting a black screen at random times while playing. There was no reproducable trigger for that. So I messed around with graphics-drivers and all that stuff. No help, so far. By accident I came to the screensaver menu and recognized that it was "Blank Screen" with 45 minutes. I turned it off and am playing for hours without trouble now.
Another guy in a German-forum reported that he had strange graphical errors during play. He recognized that this bad LSD-trip partying on his screen resembled the shapes of his screensaver. He turned it off, no trouble anymore.
So I would suggest everyone with strange graphical issues occurring during play to give it a try. (Except for you no T&L guys of course, you're doomed.
)
cicero

I had problems with getting a black screen at random times while playing. There was no reproducable trigger for that. So I messed around with graphics-drivers and all that stuff. No help, so far. By accident I came to the screensaver menu and recognized that it was "Blank Screen" with 45 minutes. I turned it off and am playing for hours without trouble now.
Another guy in a German-forum reported that he had strange graphical errors during play. He recognized that this bad LSD-trip partying on his screen resembled the shapes of his screensaver. He turned it off, no trouble anymore.
So I would suggest everyone with strange graphical issues occurring during play to give it a try. (Except for you no T&L guys of course, you're doomed.

cicero