Question about voltage levels with speedfan

Ok my PC last night started shutting itself off. the power light and all other lights were still on...it was just not working i had to unplug the power supply then plu it back in to get it to work. Earlier i turned it on it did the same thing before windows booted up except this time it didnt work when i unplugged it i went inside made sure all wires were set right etc etc and havent had a problem since (that was a few minutes ago) I read it could be power supply i recently put in a BFG 550 Watt with a Geforce 9600 GT card.

I have speedfan i use to watch my temp but im not sure if my voltage is normal so i can maybe tell it if is my power supply my reading are.
Vcore1: 1.15v

Vcore2 1.20v

+3.3v 3.34v

+5v 5.03v

+12v 11.97v

-12v -7.75v

-5v -0.58v (that one jumps all over the charts from low to high to low to high)

another +5v 5.11v and Vbat 3.12v

Anyone understand any of this?