I've got a MacBook 6,1 with Natty installed, and occasionally, usually when I'm doing something intensive, the display freezes up and becomes totally unresponsive, while the lat 2 seconds of audio loop over and over. When I reboot immediately after, however, the problem occurs again much more quickly. This, and the fact that I've never heard the fan running (though it does so infrequently under OS X) leads me to believe that something inside is overheating. Any ideas?
The fans on my Macbook 5,1 run frequently. Apple has horrible practices for cooling which I won't get into here. My Mac has the fans working automatically but I will assume that yours does not since it's tripping the built in temperature kill switch.
Is the advised solution, however it doesn't look like there is a Natty version just yet.
If you have no luck with that then try
This should help your computer detect the fans and use them accordingly.
It might be worth resetting the SMC (System Management Controller) which should enable the fans etc to automatically spin up when the temperature rises without the need for something like macfanctld or mbfancontrol