Abstract: There is disclosed a case (12) for a computer having one of a plurality of removable and interchangeable rear panels (50, 90) which provide apertures for access to I/O ports and slots for access to the rear edges of accessory cards (17, 123) of any of various mother boards (13) such as the IBM, Western Digital or Intel mother boards. For this purpose the case has a window (70) in its rear wall (22) which is generally rectangular with an extension along its lower edge. The window receives one of a plurality of removable and interchangeable panels (50, 90), each panel having a first area which is a generally rectangular recessed wall (74, 118) having a plurality of elongated slots (76, 106) that provide access to the rear edges of accessory cards, and a second area, located along the lower edge of the panel which has one or more apertures (88, 94, 96, 98, 100, 102, 104) to provide access to I/O sockets of a mother board.