Computer random power cut - voltage problem?

Let me start by saying I am not the foremost authority on pc`s and am living in Japan so manuals and the like dont mean too much to me.

Let me explain the problem. I left my sony vaio pcw-?? on one night and when I woke up it was powered down. I pressed the power button and nothing happened. I unplugged the cable from the wall, plugged it in again and the computer beeped. The power came back on and I was able to start the computer.

However, I got to the BIOS screen and was met with a message "Hardware monitor found an error, please hit F2 for details". I hit F2, went to power monitor (as the computer told me) and could find no obvious error. The mobo and cpu temps were 40-50 degrees. I did notice that the power fan stats were a greyed out N/A but sometimes it would spring to live for small bursts. The other two fans were fine. The power voltages looked strange. The +12 voltage was actually +11.3-7. It keeps fluctuating.

Anyway, the power keeps cutting out. Sometimes the computer will boot up and last for 30 mins, sometimes 3 hours, but it always loses power at some point.

The computer is one of them "all in ones", with the box stuck to the back of the monitor. I opened the case for the first time yesterday, unmounted the hard-drive to have a look for unconnected wires or the like, but its very complicated in there.

I am running a basic Celeron 2.2 processor, 256MB ram, sis 651, mobo is called KOMUGI (guess in english speaking countries it woud be pizza or summat?) no upgrades or overclocking.

Sorry if this is too vague to be helped, please do your best!

(^^;?(Though I avoided to answer, because maybe you don't want to get response from me. But no one still answered.)

I think the power fan is half-broken from its being greyed out. What about changing the fan, in any ways as you losed warranty with box opened once. It may be not so much due to power fan itself as due to the broken lead-line attached to it.

By the by, the name KOMUGI is very curious for the name of mobo, it means wheat, isn't it?

you will need to replace your PSU. This is avery common problem with many computers. They are built with crappy PSU becuase no one really cares what kind it is. Then the crappy ones die and people wounder why there computer doesn't work.

If your processor is running 40-50degrees on boot that's a bit warm. Problem MIGHT be in overheating. Pick up a can of compressed air at the local store and blow out your PC. Do short bursts with it and don't hold it upside down or else the can will get too cold and you will start freezing components. Hit the fan and heatsink on your processor first and then hit the other fans. Get that dust out of there, it acts like a blanket. Try that and post back with how it goes.

I bought the compressed air and used as suggested, but still no joy. Thanks for the support and replies everyone, think it must be a problem beyond the scope of this novice. I was thinking to just take it to a repair shop or get it sent back to sony for fixing. Would consider replacing parts if i could work out precisely what the problem was but is seems it could be a host of things.

Just a sidenote, if one has downloaded (read ILLEGAL) movies stored on one`s hard drive and takes one's computer to sony or a chain repair store, can one be held accountable and/or reported? This isnt me of course, just hypothetically...

Of that I am unsure, I say yes because someone might be able to turn one in, but I say no because it would be an illegal search unless agreed to it in the terms upon sending PC in. If possible I would suggest that a user remove said articles before allowing stranger access to files.