The invention of computer is one of the greatest advances in modern technology. It is a fairly recent invention. Computer is a substitute for the human brain. Computers are capable of doing extremely complicated work in all branches of learning. In a few minutes a computer can perform calculations that trained mathematicians would need years to complete. The fastest computers can handle millions of problems in a few seconds. It can perform many operations at a time and the same time without any confusion. Now-a-days computer has become very sophisticated and it can be put to various uses. It is already used in industries and in Universities. It can run a business, play chess or even compose music. It has great benefited us. It-has brought about revolutionary changes in human civilization.