A computer is an electronic device that processes data and performs tasks based on a set of instructions called programs. It plays a critical role in various fields such as education, communication, business, healthcare, and government. Computers are broadly categorized into different types like personal computers, laptops, tablets, and servers. The main components of a computer include the CPU, monitor, keyboard, mouse, and storage devices. This guide explores the basic functions of a computer—input, processing, output, and storage—and explains how it has become an essential tool in our daily lives.