I have been trying to persist playing through the game with this problem, however at random intervals, often at the start of a new level, my laptop completely shuts down.

Ive tried running the game on all possible resolution settings and several compatability modes, but eventually the problem rears its ugly head again. It can be quite annoying when your playing the game only for the computer to power off after a long or short time.
Also the laptop fan doesnt seem to fire up during gameplay....does this indicate a graphics card incompatability, or perhaps a direct x 8 issue?

Is there something im missing? is there a definite compatability work that is best used for Windows vista, or a setting that has proven good results for a system similar to mine?

Im running a Dell studio with windows Vista service pack 2.

Here are a few more stats if they are any help to any one.

x86 based pc with the latest bios installed
Intel core 2 duo cpu 2.4ghz
4gb of Ram
ATI mobility Radeon HD 4500/5100 series
AMD hi defiition audio device

Any tips or advice anyone could give would be very appreciated as I am enjoying the game despite the constant fear of crashing!


UPDATE:
I can run the game without issue on my old XP machine, so the issue could either be a Vista issue or a graphics card issue.
I must add that my Vista system has not had trouble running any other game and this is the first time ive encountered a system shutdown crash from within a game.