Have you checked to make sure the install and rebuild went together no problems? I know it sounds dumb, but I've disassembled hundreds of notebooks and desktops. First Apple notebook I had was a Clamshell. I replaced the HDD, went to power on and the screen wold only flash for a brief second, nothing else. Started taking it apart again, and as I was disassembling, the small connector between the logic board and the HDD was hanging off the HDD, not connected to the board. Try checking all that. I'm pretty sure that you can use a FireWire cable between two computers, with the install disc in your MB, and be able to boot the iBook and install using the MB optical drive and FireWire connection. Someone correct if I'm wrong, but never had to do that. Possible that you have a bad optical drive, or its not connected correct. Did everything work great prior to the HDD install?