Any virus will by definition make unauthorised changes to a computer, which is undesirable even if no damage is done or intended.

Chances are you’ve heard how important it is to keep viruses out, but what is a computer virus exactly? A computer virus is a type of malicious software, or malware, that spreads between computers and …

Learn about computer viruses, how to scan (and try our free virus scanner), remove viruses, and protect your computer against future infections.

Oct 8, 2025 · A computer virus is a type of program that attaches itself to a host to multiply and spread to other computers. Here's a computer virus definition, examples of viruses, and more.

Jul 23, 2020 · What is a computer virus? Learn how computer viruses spread, how to spot them, and tips to keep them at bay.

Feb 17, 2026 · A virus consists of a set of instructions that attaches itself to other computer programs, usually in the computer’s operating system, and becomes part of them.

Dec 18, 2017 · Find out what a computer virus is, what it does, how it spreads and how you can protect yourself, with examples of the most common types of virus.