PC keeps switching off

[malef!c]

Morning all.

Over the last few days the kids PC has been switching itself off or freezing up.
Thought it was heat related but all fans are fine and the CPU has had an extra dollop of arctic silver stuff on it.

Occasionally it beeps and switches off (3 long beeps I think it was) or just locks up.

I installed a small program to check fan speeds and voltage levels out of the PSU and the -5V line is showing as 0.27V, the rest are around where they should be.

Would this be a sign there is a fault with the PSU or other problems brewing?

Cheers!


edit: here is a screenshot of the PSU lines:

 

[malef!c]

Cheers chaps - will get the box out and give it a general clean out whilst I am there.

@Tealc:
- yes I did clean the original stuff off...appeared to be more of a pad originally used.
- beeps are after a random amount of time after the kids have started playing on it

As for the specs - not 100% but will check it all out when I open the case!
I have a spare PSU so may pop that in and check those voltage rail values again.