I'm currently running Windows 7 Ultimate 64 bit on my 15" MacBook Pro.
When I'm playing games on it, it gets very hot, as do all MacBooks that run Windows, but at a certain point the computer goes all narcoleptic on me and logs off and falls asleep. It is possible to just log on and continue playing, but it starts doing it more and more frequently. I'm guessing that it's because the computer is too hot, but I have no idea. My graphics card is an Intel GMA-X3100, 144 Mb.
Has anyone else experienced this?
What games are you playing? It's very possible that you're just pushing your machine too hard. Be thankful the machine shuts down if it's getting too hot though. If it didn't, you could be looking at some damage to your machine.
Secondly, what surface are you playing it on? You need a surface that is conducive to good airflow such as a desk or table.
Currently I'm playing Call of Duty 4 and Dawn of War 2. I played Call of Duty 4 when I had XP installed too and that caused me no problems. I usually place my computer on its notebook sleeve, but I could try with my desk instead.