Dell Alienware 15 (Early 2015) - Manual (Page 115)

3 Using the pull tab, disconnect the hard-drive cable from the system board.
1 pull tab 2 hard-drive cable
3 power-adapter port cable 4 computer base
5 fan cables (2)
4 Turn the computer over.
5 Lift the latch and disconnect the I/O-board cable from the system board.
6 Disconnect the speaker cable from the system board.
115