pc stalls not working

[lukeplechaty]

my pc completely stalls after about 5 minutes sometimes it reboots and all usb voltage are not working or the computer just stops working.
From my knowledge it sounds as if Its a power problem But haveing speedfan up it look ok but the -5v is 4.73v and the -12v is 0.47v.
any help?

 

[Calvin7]

What are the negative voltages used for? The answer is, not much! In fact, –5 V was removed from the ATX12V 1.3 and later specifications.

The only reason it remained in most power supply designs for many years is that –5 V was required on the ISA bus for full backward compatibility. Because modern PCs no longer include ISA slots, the –5 V signal was deemed as no longer necessary.

Although –12 V and –5 V are supplied to the motherboard via the power supply connectors, the motherboard normally uses only the +3.3 V, +5 V, and +12 V. On some motherboards, the -12V and -5V lines are unnecessary for them to function, so your third party software may be recording an inaccurate voltage reading.