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

May 22, 2025 · Like other programs, it’s defined by what it does, and the big thing a virus does is replicate itself. The virus exists as a collection of computer instructions attached to another program,...

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.

Feb 29, 2024 · Hackers spread computer viruses by creating malicious code that can get inside a computer system, modify it, and spread to other computers. A virus infects devices and spreads by …

Jul 23, 2025 · A computer virus is a type of malicious software program ("malware") that, when executed, replicates itself by modifying other computer programs and inserting its code. When this …

Computer viruses spread across systems, infecting programs & files with malicious code. Learn to scan for viruses (and try our free virus scanner), remove viruses, and protect your computer against future …

Mar 17, 2023 · A computer virus is a program that spreads by first infecting files or the system areas of a computer or network router's hard drive and then making copies of itself.

Computer viruses aim to disrupt systems, cause major operational issues, and result in data loss and leakage. A key thing to know about computer viruses is that they are designed to spread across …

Jul 16, 2025 · A computer virus is malicious software crafted to replicate, spread, and cause harm. Think of it as an unwelcome guest wreaking havoc in your home—but instead of throwing parties, it’s …

Dec 16, 2025 · Learn what malware is, how it works, the most common types (viruses, ransomware, spyware, etc.), and effective ways to protect yourself and remove infections.