They spend hours dreaming up new strategies to infect computers, then hours more bringing them to reality.

On the other hand, a worm is a program that actively transmits itself over a network to infect other computers.

It might infect computers through e-mail messages or corrupted Web links.

Viruses usually infect personal computers, spreading through floppy disks and copied programs.

The 3wPlayer employs a form of social engineering to infect computers.

The distinction is important because viruses can copy themselves and infect other computers, often without user intervention.

Whenever the infected program is run, the virus reproduces and tries to infect other computers.

It was first analyzed on September 18, 2003, however, it might have infected computers before then.

He wrote a short program, as an experiment, that could "infect" computers, make copies of itself, and spread from one machine to another.

Viruses are relatively small programs that hide in other programs, waiting for a chance to infect new computers, duplicate themselves and spread.