OS X :: Forced Shut Down Now Hard Drive Has Vanished?

Black 2006 Macbook, running 10.5.8. Refurb so no restore discs, but a retail copy of Leopard.

I did something truly stupid, I was reading on here about selecting different libraries when opening up iTunes. I thought hey I'll see if I can bring up my Power Mac G5 iTunes library (also running 10.5.8, where all my music is kept) and have it in a full library rather than the home network sharing option which doesnt have artwork etc.

Anyway...

I hit shift+alt when opening iTunes and navigated through my shared folder to the PM's music folder and selected the library file. iTunes bounced for a bit then the whole thing just hung. Stayed in a beachball and wouldn't let me force quit either. So I held the power button down and did a forced shut down. When I booted it back up it took me the grey screen with a flashing folder and question mark.

I popped in the Leopard retail disc and booted from that, opened up disc utility to find my harddrive has completely vanished, the only thing showing is the optical drive.

Ive tried:

Booting into target disc mode with the Macbook connected through Firewire to the G5... the G5 sees it in shared, as the computer name that I gave it (which must mean there's something there if my settings have been stored?!?), but fails to connect. It did connect as 'VNC' once. But there was nothing in the folder.
Tried resetting the PRAM.. not sure that would do anything but I thought why not, chimed twice but still doesn't see the hard disc in Disc Utility.

Booted with D to force the Macbook to boot from the internal, it just stays on a grey screen forever.

Tried to select startup disc but the only things listed are the Leopard install disc and a network boot. Also tried going ahead with a leopard install, my stuffs backed up on disc and the G5 so I dont mind a clean install, just want it to work again! No drive listed to install to though.

Any thoughts at all?! Can't believe I managed to destroy it with a tiny action!