MacBook black screen on boot, no chim

"If you interrupted the firmware update process you could have corrupted the systems firmware which may not be possible to fix by your self.

As you don't hear the chime it supports you most likely messed up the firmware but it's also possible to disable the chime so in its self it may not be enough of a clue here.

Can you start your laptop from the OS-X install DVD that came with your system at all? Does it appear to load up but you just can't see the display? It's possible the back light is not lighting up. In strong light can you see a faint image in the display?

If you can't see anything and you did nothing else to your system then it's likely the firmware is messed up. In that case I don't know of any way to fix it and most likely will need to be serviced by Apple directly.

The only way I can see here to access the files on your HD is to remove the HD and place it into an external firewire HD case so you can access the data on your iMac. Without any 'brains' in the Macbook you won't be able to get it into disk mode to use the firewire cable interconnect.

If you can see an image on the display you should be able to put the system in disk mode so you can at least copy off any needed files. If you can see enough of the display you could try running the firmware update again and hope it is able to fix things. Otherwise it's time to get to the Apple Store and see what they can do for you.

Sorry ;-{"

Reminds me a lot problems with CMOS batteries on older Macs, had the chime but no no screen activity. Have you tried replacing the PRAM battery yet?