Dead PC

[furtive]

Replaced the case and PSU of my PC and when I powered it on there was a small pop and tiny spark that looked like it came from the back of the power switch inside the machine and some of the magic smoke was released. The case fans spin up but the CPU fan doesn't (although it still works if I plug it straight into the PSU power) and the machine doesn't boot

Motherboard isn't shorting out on the chassis, so what could have caused it?

Duff case power button? Duff PSU? Something else?

[Ozone]

You could try running the main board and psu out of the case to see if anything happens and then add more cards.

[mattley]

Either one of the rails gone on the PSU or a smoothing Capacitor on the MoBo, probably the latter if the magic smoke didn't come out of the PSU. Inspect the MoBo as any magic smoke escape route will probably be visible.