Abstract This work has been designed to assist computer engineers to effectively diagnose problems in the computer sub-system, such as hard disk, floppy disk, drives, monitors, keyboard, etc. Equipped with this system the user can easily detect when a particular sub- system is faulty. This program is developed with Visual Basic programming language and is designed to run in any DELL. Basic programming language. It is also designed to run in any DELL capable computer loaded with MS-DOS- A flow chart is used to enhance the understanding of the program. The program is structured to actualize the objectives of the design. Some graphic features in the design make the whole design palatable and isolating faulty components has been reduced.