Can you please attach the minidumps relating to the crashes in your next post and I'll ask our crash dump expert to have a look at them for you. Please see link below for how to attach the minidumps.

http://www.pchelpforum.com/windows-x...eath-here.html

One last thing you can try if you haven't already is to update nforce chipset drivers for your motherboard. See link below:
nForce Driver

I dont get a blue screen it just shuts off my PC

Are you able to check if there are any minidumps or any errors listed in the event log just in case?

Have you checked that your nforce chipset drivers are the latest ones as per my post?

yes drivers are all up to date and no errors listed in the system

I'm really not sure why your getting this problem. Could the motherboard be shorting out on the case? Check that any of pins on the back of it aren't longer than the rest.

Get winlancherxp
Setup your game to run on only one core.
This has worked for me.

The pins are all the same length its not touching the case.