computer virus
What is computer virus. = A computer virus is a destructive program that corrupts other programs. Write its symptoms. = The symptoms of computer virus are: (1) Programs disappear from the computer. (2) Files or programs take a long time to load. (3) Programs start automatically without any instructions. (4) Change the size of disks and files. (5) New programs do not get installed correctly. (6) Frequently display unnecessary error message or images.