Incredibly, the development of Technology is increasing day by day. There are more and more demands for using the technological appliances by individuals, agencies. Moreover, the 4.0 technology is being widely applicable. Desktops, laptops are gradually being used for work, with more and more demands. However, it is not always possible to call a technician to check your devices. Due to these, you should be a computer doctor right now, right away so that you do not need to call a technician anymore. This document will help you become a Computer Doctor. The book is designed to facilitate the students to well acquire knowledge related to the subject. This is a reference for students of information technology faculty of universities, colleges, professional secondary schools.