The event that causes a virus to act. The trigger can set off the
virus on a certain date (Friday the 13th, or April 15) or when certain
conditions have been met (such as when the hard disk is 80 percent
A type of program that pretends to be a useful (usually
well-known) program while it really does something else, such as erase files
from your computer. Unlike computer viruses, Trojan horses can't duplicate
Operating system originally developed at Bell Laboratories in the
early 1970s. Unix is one of the most popular operating systems in the world,
developed primarily for larger computers, such as mainframes and minicomputers,
although a free version of Unix, called Linux, has been gaining popularity on
personal computers. See
A type of antivirus program that claims to protect files from
A program that hides in your computer's memory and watches for
signs of a virus infection.
A program sold by Microsoft that lets you visually design a
program and then write BASIC commands to make the program
A special version of Visual Basic, often abbreviated as VBA,
designed for creating programs within Microsoft applications such as Word,
Excel, PowerPoint, and Access.
A program that can dial a range of phone numbers, searching for a
modem on the other line. Can also be used to repetitively dial a single phone
number, thereby harassing the recipient. Also called a demon
Slang term for pirated software, usually games. Also called
To restart a computer without turning it off and on again. Most
computers have a restart or reset button, or you can press
A tiny, invisible graphic file used to track a person's
activities on the Internet.
Modifying or replacing web pages with new ones that often display
profanity, pornography, or political messages. See
To intercept a user's request to view one website and display a
different Web site with the intent to deceive.
Term used to describe a hacker who uses his or her skill for
constructive purposes, such as hunting down pedophiles or guarding against
malicious (black hat) hackers. See
Black hat hacker.
A type of program that copies itself from computer to computer.
Unlike a virus, a worm doesn't infect a file or disk but simply reproduces
A program that can combine two separate programs into a single
file, most often used to combine a Trojan horse installation program with an
installation program for a legitimate program. Also called a
binder or joiner.