have you tried reconnecting the audio/wifi board inside the laptop?
steps:
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unscrew everything on the bottom case, pull out the DVD drive
remove the keyboard, disconnect all flat cables
open and remove the top case
remove all the "B" screws on the motherboard
disconnect all power and speakers wires
on the right bottom of the motherboard, it connects to audio/wifi board through a narrow, 3/4 inch long, snap-in connector
now, reconnect this audio/wifi board
put everything back...