An alignment device eases installation of computer assemblies, such as drives, into a corresponding chassis. The alignment device includes one or more planar areas located and oriented so as to be substantially alignable with one or more computer assemblies to be mounted to the chassis. The computer assembly has a user-visible surface which is moved until it is co-planar with a corresponding planar area of the alignment device. When positioned in this co-planar configuration, the computer assembly is correctly positioned relative to the chassis to be mounted thereto. The alignment device can be located on the computer chassis between mounting locations for two computer assemblies, such as a 5¼-inch drive and a 3½-inch drive and, in such application, can be provided with two planar areas at two different heights, one corresponding to the alignment position for one of the computer assemblies, the other corresponding to the alignment position for the other of the computer assemblies.