[Presto]

At this point, I'm wondering if your computer is attempting to boot at all. Even if my screen isn't on, there's evidence that the computer is still doing something. When switch it on, I'll hear the hard drives spin up, and then a beep as it goes through post. After post, I'll see the light blink like crazy for disk activity, so I know Windows is starting up. If you can't be certain your computer is performing the normal startup process (minus video), then perhaps it's a problem with the motherboard or something else, like the power supply.