Precision 690 problem, aux voltage?

Hello,

I have a Dell precision 690 workstation.

The problem I have is that the computer would sometimes shut off itself (by going through the actual Windows XP shutdown process, asking if I want to save my documents, etc). Afterwards, if I try to turn it on, it would not go through the Dell logo screen, or just turn itself off randomly before reaching Windows Xp booting screen.

I downloaded a hardware sensor monitor from http://www.hmonitor.net/ and it indicated that my Aux Voltage is +0.15V.

I then found out that Aux voltage is supposed to be between 1-5V ?

Can anyone with a Precision 690 tell me what their aux voltage is... and if my Aux voltage is too low, do I need to change my power supply? (where, how, can't seem to find new ones on Dell website)

Thanks