WHAT IS A VIRUS ?

A Computer Virus is a computer program that can replicate itself and spread from one computer to another . Otherwise we can say computer viruses are small software programs that are designed to spread from one computer to another and to interfere with computer operation. Depends on the nature of a computer virus it may cause damage to your computer system. In most cases if a file that contain virus  is executed or copied onto another computer ,then that computer will also be infected by the same virus. A virus program contains instructions to initiate some sort of event thet affect the infected computer system.  Or simply we can say  a computer virus is a piece of code that is loaded onto your computer without your knowledge and runs against your wishes.