Shuttle keeps power off

I brought a new shuttle on the advice of an ex-friend and the damn thing just powers off. I can happen when I load up a game or it can happen when I am hust idling in the bios. It happened a lot during windows installation. I thought it could be the ram, but I have tried three different sticks and it does it on alll of them. The all work perfectly in my other system which also has an 2500XP chip in it. It's the SN45g Shuttle. I noticed that in the bios there is no cut off temp option. I looked for an update of the bios, but the files are bin's and I can't convert the damn things to ISO. I can honestly say everything about shuttles suck. They are scum!
PLease help me

Hey bud do you have the heat shield around the right way?

BIOS images are in .bin format, you dont need to convert them to ISO. Get the bios flashing utility from the shuttle website, put it and the bin on a floppy and bobs your uncle :)

If a shuttle keeps powering off its overheating.
Check:
the thermal paste is on the CPU
the fan is plugged in
fan not permanently on 'low speed' setting
fan is blowing air out of shuttle not blowing in.

had this problem on a desktop recently and it turned out to be the powersupply after 14 hours would switch off

mine powers off to. but i have a bad power switch. does anybody have the wiring diagram for it. or somewhere i can get it. they put it on a circuit board, not like the towers. any help would be great