Use a tape measure to measure the length and width of your CPU. Add 1 inch to each measurement for extra space.
Transfer the measurements to a piece of 1/4-inch-thick plywood. Use a wood saw to cut out the rectangle for the CPU platform.
Cut two 1-inch-high strips of 1/4-inch plywood the length of the CPU platform. Place a small bead of wood glue to attach these strips to the CPU platform.
Connect the strips permanently to the CPU platform with 3/4-inch finish nails.
Cut two 1-inch-high strips of 1/4-inch plywood the width of the CPU platform. Place a small bead of wood glue to attach these strips to the CPU platform.
Connect the strips permanently to the CPU platform with 3/4-inch finish nails.
Place one caster near a corner of the CPU platform. Use a screwdriver to attach the caster to the bottom of the platform. Repeat to connect the other three casters to the platform.