[Hampshire] Resurrecting a dead PC

This is the worst possible time for the kids' PC to die - just as I'm about
to go away for a few weeks!! Grr!
Anyway, I am not sure what the faulty component would be, so I have once
again turned to the trusty group!

The problem is that nothing at all happens when the power on button is
pressed. Looking at the Motherboard, it has a red led lit up, so presumably
it isn't the power supply. My guess is that somehow the MB has got frazzled.
I suppose it could be that the CPU is dead, which I'm placing a close
second. Any second opinions would be gratefully received.

Thanks

Kelvin