Comp shuts down when running sl

i am having a very odd problem with sl, it seems my comp will shut down randomly when i play it, the first time it happend i was on for maybe 10 mins, could not even restart my comp it was dead for all i knew, an hour latter it was back on and working fine, did a virus scan and found nothing amiss, loged back on to sl and sent a crash report like i was asked, was on for only 2 mins and it did it again, could not turn it on again, came back 10 mins latter and it was on, has been on for a full day now and no problems, i can run wow-eve-ffo3 and many other games for hours on end with no problems, i am lost as to what this is? my specs are:
windows vista 32bit
intel dual core 2 2.6gh
2g navidia 9600gt
4g ram

ty

Heat?

Sounds like a heating problem. If you are on a laptop you might want to get a cool pad for it. And make sure you are not actually setting your computer on your lap while on SL (or any other computational and graphically intensive program). If you are on a desktop you might want to take the side of the case off, get a can of compressed air and thoroughly blow out all the dust inside the case. Blow air through all the fans, including the CPU and GPU fans, and don't forget the power supply. All the fans should turn freely when you blow the air through them. Make sure the placement of your case is such that air can freely enter and exit the computer case.

Go online and download PC Wizard 2008 (it's free........Google PC Wizard 200 and monitor your tempertures while on SL. Any temperature approaching 95 C is getting close to critical. Main components that will heat up are your graphics card and CPU. So watch those closely.

should have mentioned its a desktop XD, it migth be heat, did not cross my mind to be honest, i have dual 250mm fans blowing onto my comps insides, one of wich is directly over the gpu as well as the gpus own fan, free of dust, just ran sl for an hour seemed fine this time, hopfuly it wont happen again as i am already in love with this game in the short time i have played tyvm for responds

I agree with this. Mine also shuts down and won't restart until cool enough. One thing I have found which stops this happening is setting the client to only use 1 chip. This can be done using task manager....right click the SL client there and select "set affinity" and de-select one of the chips.