A customer just brought in a MacBook Pro 15" with the sound and Airport card not working (they don't show up in the hardware config window, just greyed out). He said that someone had recently replaced the hard drive.
While taking the computer apart, I noticed the the speaker wires that plug into the IO/Mag board had been routed under the hard drive's ribbon connector. This was causing the wires to be crushed. Looking at them now, I can see that they have flattened.
I'm thinking that the crushed wires may have caused a short in the IO/Mag board causing the board to not function properly and perhaps killed the little board.
I did test with another Airport card and it won't show itself either.
I think the best thing to do would be to replace both the speakers/wires and the IO/Mag board.
Does this sound like the right thing to do?
Anything else I should be aware of/look at?
Thanks,
Edison

Sounds good to me. That is what we would recommend.