What is a Computer Virus?

A virus is a computer program (usually disguised as something else) which is designed to cause undesirable effects on computer systems.

Viruses are often designed so that they can be transferred from one computer to another without the users knowing.  They can be hidden in e-mail’s, on CDs or in files that are shared across the Internet.

Computer viruses can cause harm to computer systems and need to be avoided.

Computer programmers called hackers often use viruses to stop or slow down computer systems.