No sound on Powerbook G4 laptop

So my brother gave me his Powerbook G4 Laptop (not quite sure which one it is, but it is probably about 2 years old, all silver with the 17" screen) after he got a new one. I'll pop open the back if yall need to know exactly which one it is.

Only problem is, it has no sound. In the sound preferences, for input, it says for name = "headphones" but for port = "built in audio." I thought built in audio was for the computer's speakers?
And there are no headphones attached.

When I hooked up some external speakers, they did not come up as a choice, even after rebooting the computer. However, they did make some sounds, but would not play a cd or anything on the computer still. I tried the plug in unplug plug back in thing, but that didn't work.

The computer did crash completely about a year ago (it had this problem before though) and the dudes at the mac store supposedly fixed it...but I guess not the sound thing.

Any ideas? Thanks!

is the cd playing on the computer but you just don't hear sound? on the keyboard in the function keys there is a mute volume up and volume down. could it be on mute?

thanks...no i already checked those though, unfortunately that was not the case. Though today, after plugging and unplugging some external speakers it now says for my input internal speakers (so that is good) instead of headphones but the sound still isnt there.

when i move the sound volume up and down, it makes this extremely faint sound, as in I have to put my ear to the computer to hear it. cd - still no sound.

no one else? for the people who have had this problem in the past, what exactly needed fix internally and how much was it? thanks!