Mac problem...desperate

So, I was installing bootcamp on my Mac, and the Windows Installation wouldn't complete. For some reason, when I turned the computer back on, all I got was a grey screen.

Booting from the OSX Install CD didn't work, and other various things the support people suggested didn't work either. Finally, they said that the computer was responding as though there wasn't a Hard Drive inside, and to take it to an Apple Service Station place or whatever.

My dad took it today, and apparently they refuse to perform service on it because it's a "software" error (even though the problem as diagnosed by the Apple Support people is that the computer is physically not recognizing a Hard Drive).

So, basically I'm wondering if there's any way for me to tackle this problem on my own without voiding my warranty. The keyboard only stays responsive for a little bit after I power up, but then stops responding.

Jam it back in, in the dark.

Holding C when I turn on the computer. I also held the option key, which did nothing, and I pushed the power button for five seconds when it was disconnected at the request of the tech guy at Apple Support.

Also, as it turns out, they didn't outright deny service as I had been told by my mom through the phone. They referred it to the Software guys, who in turn referred it to the Hardware guys, none of whom know what's wrong.

I frigging know what's wrong, I just can't fix it because I can't open the computer ;_;

There's nowhere I can't reach.