What is virus?

is a computer program that can copy itself and infect the computee with any permission and user will not know it. and this also can spread to other computer.

virus is a small application which is used to harm ur system happy lotting and have a nice day

A computer virus is a computer program or peice of code that is loaded onto your computer without permission or knowledge from the user. It runs against your wishes, and can copy itself. All computer viruses are man made and even a simple virus can be dangerous because it can quickly use all available memory and bring the system to a halt. An more dangerous type of virus is capable of transmitting itself across networks and bypassing security systems. Viruses are designed different, depending on the task the programmer wants. Some are programmed to delete a file or a series of files, some to destory a computers operating system and some just to annoy you.