By Katherine Teitler


A computer virus is a malware, or malicious software, program. What makes viruses unique is that they replicate themselves by inserting copies into programs, files, or the boot sector of a computer’s hard drive. Once a virus takes hold, the computer is said to be “infected,” and the virus can access, change, steal, or delete data, affect the operation of the computer, spread to other computers, sap memory, or “crash” the computer, among other payloads (malicious activity).

Viruses can move from computer to computer without  users’ knowledge, but for the virus to spread, it requires some user action, like clicking on an infected link, visiting an infected website, or opening an infected attachment.