So it's been many years since I tinkered with PCs - I think the last one was a 486!
The shop PC, a reasonably powerful tower that I swapped a customer for a Brompton, has gone on the blink. For a couple of days it was freezing randomly, then coming back to life, but now it won't turn on at all - no lights, no boot-up, nothing apart from a whine from the power supply (though it did that before).
Would I be way off in thinking it's probably the power supply? The PS seems to do something - a red LED on the motherboard lights, and it powers USB ports - but no fans start up. Or is it more likely a dodgy motherboard?