You will need a putty knife or small paint scraper to remove the Mac Mini's casing, a small Phillips head #2 screwdriver, a pair of tweezers, and either a replacement 2.5-inch solid-state drive or a hard drive. It also doesn't hurt to pick up a can of compressed air to clean away the dust.
Gently shimmy the putty knife between the base of the Mac Mini and the case. Carefully bend the knife away from you until the cover begins to lift as you make your away around all four edges.
There are three orange antennas that must be removed before moving forward. The two on the left simply lift out, while the larger one is held in place with a clip that must be squeezed from the bottom.
Unscrew the four screws that hold the CD drive into place. Make sure you are removing the screws that connect the drive to the case, and not the ones on the actually CD drive.
Secure the hard drive in place, reattach the temperature sensors, and place the CD drive back into the case. Use the four screws to secure the CD drive, and reattach the ribbon cable. Then, take the three springs you removed earlier and place them back on their corresponding antenna posts, followed by the antennas themselves. Place the case back on the Mac Mini and push down evenly along the edges to lock it in.
