As for the modem, it is in there. I've never used it, so I've no way to know if it has simply gone from not working to system halting. Ribbons are all seated, I have no other duo parts. It does the same thing docked. The HD doesn't spin up(but I think that is a sympton, not the problem or I'd be getting a ? floppy). I'll try and find some more death chime info...

*Although... the chime is pretty sweet for a dead duo; 4 nice notes and then 4 increasingly creepy and weird sounding notes. It fits kinda well for something that is not quite alive, not quite dead

EDIT-This is vaguely helpful...

"Everything snapped in well and was basically plug and play. However, on first boot, the machine did the dreaded chimes of death - but there was no Sad Mac. A quick bit of research revealed the longer tones experienced were from the RAM."

Could it be the PRAM battery?