My teenage son ended the system process from task manager after noticing that it was using 100% CPU. Is it possible to recover from this. Our home PC is now totally dead! - It will not even power up. I have checked the PSU and all of the voltages are ok. The PC was running XP.

It's not powering up as in the fans aren't spinning and you get no lights or does it restart when you try?

If it's not doing anything at all it's a hardware issue and ending a system process wouldn't cause this.

If you can give us a few more details I'm sure we can get it sorted

-Lebowski

Thanks.
I'm pretty sure that it is not a PSU issue as I followed an on-line guide, removed the psu, connected 2 of the motherboard connectors and measured all of the ouputs: +5v, -5v, 12v, 3.3v.
With the PSU connected back in the base unit absolutley no response from anything ie, from fans or LEDs. I've tried removing the power to the CD and HD + removed the expansion slot cards (graphics + TV) to see if anything will spin up - but it's still dead.

I agree with The Dude...Ending a process will not make a pc unbootable..

I can give you some ideas to help see if this fixes it..

1) Bad CMOS...I do not think it is this but...Open thew case and you will see a little silver battery..Take it out for a good 30 seconds replace and try to boot up again..
2) This will test if it is either you motherboard or power supply..
Open the case (Please leave it plugged in)
Take a Standard Head Screwdriver and down at the right hand end of the motherboard you will see little wires going into prongs..Find the one that says sys power on or something similar and rub the screwdriver against the 2 prongs.. It should short it and turn on the pc if your motherboard is good.

I would ask your son what else he did..(Not to get the poor fellow in trouble lol)

Thanks Merlin.
I have tried both of your suggestions and still no go.
I think I may buy a compatible motherboard as this seems to me the most likely cause. I can pick one up for about $50.
Thanks again.