Boot it while holding down T, so that it boots as a firewire disk. Connect it to another machine and see if the disk comes up. If it does, it's not the disk.
Try booting with cmd-v to get verbose mode (might tell you what's wrong). Se http://davespicks.com/writing/programming/mackeys.html for other boot options.
Try booting with cmd-v to get verbose mode (might tell you what's wrong). Se http://davespicks.com/writing/programming/mackeys.html for other boot options.