I just downloaded the demo and played it several times. However, the game occasionally just stops working and my computer becomes unresponsive (ctrlaltdel , altf4 dont work) and I have to restart the computer by holding down the power button. I have vista on a fairly new HP (AMD 64 dualcore, 3gig ram, decent nvidia card). The game runs very smoothly and has no other problems.

I really enjoy this game, but am not sure whether to buy it because of the aforementioned issue. Does anyone else have this problem or could give me any advice? Is this only a demo related issue? I would appreciate any help!

Thanks!