I don't think the psu is the problem at least at this point.
Usually the motherboard manufactuer supplies a program on the motherboard cd that reads temps and volts.
You could also try Everest
http://www.majorgeeks.com/EVEREST_Fr...ion_d4181.html
Or SensorsView Pro
http://www.stvsoft.com/
Tell us the temps when at idle and when playing the game
Tell us that error too