Computer viruses have an enormous potential for very serious damage to our computer system.
Our computers crash, data disappears, productivity loss, and entire networks can go down.

Viruses can inflict major damage on our corporate network.

The term "Computer Virus" covers many types of malicious computer code. As with a biological virus, there is more than one "strand" that can attack our network, since many viruses and other malicious code are often designed to exploit weaknesses in particular computing platforms, network environments or user "cultures."

What Is a Computer Virus?
A virus is generally defined as a program that infects documents or systems by inserting or attaching a copy of itself or by rewriting files entirely. A virus operates without the knowledge or consent of the user. When an infected file is opened, the embedded virus is also executed – often in the background. A true virus is propagated by users themselves, almost always unintentionally. A virus does not deliberately spread itself from computer to computer. It may replicate itself within one computer, but in order to propagate to other machines, it must be passed on to other users through infected e-mail document attachments, programs on diskettes, or shared files.

New malicious code strains have made self-replicating viruses more common. A simple virus may propagate itself and then allow the program to run normally. Most viruses, however, deliver a "payload," or malicious act. For example, the virus may be programmed to display a certain message on the machine's computer screen or perform a deletion or modification to a certain document (or some combination thereof). Especially dangerous viruses do irreversible damage, such as deleting entire user or network files, or reformatting hard drives. Others may simply wreak havoc on network systems by spawning processes that in turn spawn other processes, eventually bringing the system to a halt.