Abstract: A computer case assembly that requires few or no screws for assembly includes a chassis that comprises a frame with side panels forming device bays for computer accessory devices. At least one of the side panels includes substantially parallel horizontal protrusions along the interior surface of the panel. A mounting rail has a screwless attachment for applying the mounting rail to a computer accessory device. The mounting rail is configured to slide between the protrusions of the side panel, and includes a latch to engage the chassis frame members. The chassis also includes a rear panel and a motherboard panel attached to the rear panel. The motherboard panel and the attached rear panel may be moved into a position in which the rear panel is substantially flush with the rear of the chassis. When the rear panel is substantially flush with the rear frame members, a latch affixed to the motherboard panel engages one of the rear frame members.