Remove the three T9 torx screws then the two phillips PH 0 long screws.

Pull up on the left side (the side without the four wires), then on the right side. The right side of the power supply will be harder to pull up on so you'll need to pull firmly.

After you get it loose you'll be able to pull it up a bit but it will still be connected by the four wire connector so don't pull it all the way out until that has been disconnected (shown in the next step).