Computer viruses are called virus because they share some of the trails of biological viruses. Computer virus passes from computer to computer like a biological virus passes from person to person. Computer virus must piggyback on top of some other program or document in order to get executed. Once it is running, it is then able to infect other programs or documents.
Biological virus is a fragment of DNA inside protective jacket.
Instead, virus must inject its DNA into a cell. The viral DNA then uses the cell s existing machinery to reproduce itself. How viruses work. Any virus is designed so it runs first when the legitimate program gets executed. The virus loads itself into memory and looks around to see if it can find any other programs on the disk.