Step 25
Disconnect the large multi-colored power cable from the left I/O board.
Step 26
Remove the following 5 screws/standoffs:
Four black T6 Torx screws securing the left I/O board to the lower case.
One 4 mm standoff located between the audio jacks.
Step 27
Lift up the right side of the left I/O board and slide it out of the computer.