Although I was very careful with the speaker cable, and everything else, I too get no sound from the speakers after otherwise-successfully replacing the HDD. However, I also don't get any sound from the headphones either. Can that cable affect headphones too? Update: To further clarify, I haven't yet had a chance to do much diagnosis of the problem, other than the obvious stuff: Yes, the volume's up, it's not muted, and the correct (and only) sound-output device is selected. After it finishes a round of Software Updates, I'll try zapping the PRAM (what the heck, may as well).