[WernherVonTrapp]

OK, I see you have only 2GB of RAM. Now, I'm not saying that's the problem because, right now, my suspicion is based solely on conjecture. Nevertheless, so far, my prediction is correct (that is, I suspect the problem may be RAM related). Mind you, I'm simply trying to help you troubleshoot a problem. If you can accommodate a bit more, please play SHIV until the problem occurrs again and then, save and close-out the game. Follow that by rebooting your system and see if that doesn't correct the problem.
Now, bear with me because, I fully expect the problem to occurr again, (being RAM related that is). What I'm trying to find out (with your help) is that, upon rebooting, does the game last longer before the problem reappears again? If it does, I would recomment a RAM upgrade (i.e., more RAM).