Ok, If your PC works well before the deadly power cut, and now 'died' after that, there's no need to think much.
& what do you mean by that 'power cut'? do you mean it's a lightning strike that cut the electricity power of your house? If so, maybe the lightning sent a powerful source of power from your house's electricity to your pc (that your pc power supply couldn't afford to bear the overwhelming power sent by the electricity flow (wire). This is also possible to kill your pc. I hope you understand what I mean (fheww.. english is sure tough to 'perform')
1. Turn on all power, push the 'ON' button of your CPU. This won't turn your computer ON but the purpose why I ask you to do this is to check your computer power supply. Give a sharp attention to your power supply fan (usually visible from the back of your CPU). While the 'wall' power is on, try to push the ON button continuously while checking whether your power supply fan is spinning.
2. Does it spinning? No right?? If not spinning, then you don't have to use that power supply again since it's 'dead'. Try replacing it with a new one. This surely solve the problem. (I think).
