Hi, 'tis me again with PC troubles...

This time, it's not the uni wireless or anything like that, it's something more serious. Specifically my PC has decided to relive a problem it experienced when I first got it (around late July, possibly August); it refuses to boot up. One minute it was fine, all running nicely, then I shut it down to head to uni for a bit, came back, turned it on to do surfy stuff, and not much happened.

Basically, when I hit the power button, this is what happens:
-The power light, and motherboard light comes on
-The fans start
-The DVD drive does its thing (so I know that's getting power at least)
-Absolutely sod all else.

The keyboard won't respond (not even the 'lock' lights work), nothing's coming through to the monitor and the onboard sound thingy isn't working, so no reassuring 'beep' when BIOS comes up (which might not even be doing that anyway; I can't tell with no display), and the HDD light that usually happily flashes away during startup isn't doing anything. Oh, and another thing; it won't reset with Ctrl-Alt-Delete either, which is weird. And the mouse doesn't seem to be getting any power either (the optical bit won't light up).

Anyone any idea as to what the frig gives?