There are eight 3.5mm screws that hold the motherboard in. Use a T-5 Torx screwdriver to take the screws loose. These screws are outlined in a gold color on the motherboard.

Two gold colored screws with brackets are located in the orange circles. A T-5 Torx screwdriver is needed to take these 3.1mm screws.

Motherboard should lift out easily and completely.