Why doesn't my mac startup after a failed zero writing?

Hi all,

I'm on a macbook pro, os x 10.6 snow tiger. I had only 10GB of free space on my disk, and I decided to write zeros over it. By accident I interrupted the writing and the free space became a temporary 10GB file, which left me with a full disk. I found the file and moved it to the thrash but got an error message when trying to securely erase it. I verified the disk with disk utility and got a message telling me to restart the system with the installation disc on it. I did, and since then I cannot boot my mac again: it makes the startup chime, goes to the gray screen with the "clock" ticking under it, but stays there forever.

So far, in no exact order:

-Tried solo mode and fsck -fy until i got the "The Volume Machintosh HD appears to be OK";

-Tried booting with option pressed, and then tried both the installation disc and the hard disk... both got the mac screen frozen once I clicked at them;

-Tried putting the install disc on a pc and through ethernet to acces the disc on mac;
-Tried leaving the macbook boots for 10 minutes...

-Executed a hardware test;

-Tried booting on safe mode.

Nothing worked and I have no idea how to repair the disk. I wonder if there's a way to delete the corrupted temporary file or any other way to make it work. Any help would be highly appreciated. Thanks in advance.

ps: I found a website in which they charge for remote advicing, I would even pay for a solution, as long as it really works.Anyone had any success with such online services?