Macbook won't boot at all

[mymacisfsck'd]

My macbook won't start anymore. It will happily reach the screen with the apple and status bar, but when the status bar reaches the end it just hangs. I have tried to boot from CD but you can hear the drive spinning up but it just hangs at the apple logo with the spinning cog underneath. I have tried single user mode, but no joy there either.

Anybody got any ideas?

Cheers