Originally posted by firewire2001
you can jus look at the serial on the bottom of the computer....
Actually, this happened to me with my rig (G4/533). My problem was taken very seriously by Apple Support. Tier-2 support was calling me 2 or 3 times a day to give me a list of things to do to try to get it to appear again. None were working.
They seemed very anxious to get to the bottom of the "missing" serial. I think this problem is rare, but it's obviously something Apple dosen't like.
Luckily enough, by HD failed (a ball-bearing popped out) and they replaced it free, of course, through AppleCare. When I booted the machine my serial was back. Never had that problem since.
PS: One thing that still occurs from time-to-time is when waking my machine from Sleep, my audio goes mute and there seems no way to get it back (mute button is unchecked and I can still control volume - no sounds though). I have to reboot and then I've got my sound back. Does this happen to anyone else.