Computers are modern electronic machines that are used for doing various programmers. The person operating the computer gives instructions and thus the computer works. A computer stores "formation in its memory and uses whenever it is needed. The person gives instructions to the computer in a language that a computer understands. The most common computers are PCs They is found in homes, school, and office throughout the world. The main parts of a PC are a centre processor with its disk drives, keyboards monitor, printer and a scanner. They have become important part of our lives.