Computer viruses are malicious programs that can copy themselves and spread from one computer to another. Malware is harmful software installed without consent that can collect user information secretly. Computer worms are self-replicating programs that use networks to spread to other computers without needing user interaction. Antivirus software detects and removes malware like viruses, worms, and Trojan horses to protect computers.

1. Computer Virus A computer virus is a computer program that can copy itself and infect a computer.