After waking up this morning, I pressed the power button on the CPU to turn it on, but nothing happened. When I mean nothing, I mean absolutely nothing happens. No lights, no whirr of the fan, nothing coming to life. It just sits there, dead.

How could my computer just suddenly die out like that? And what's the problem? Power supply? I may or may not know the answer, I need a confirmation. So talk to me, people!