Give a detailed definition and explanation of what a computer virus is.

A computer virus is a type of malicious software that is designed to infect a computer system and spread to other computers. It is typically created by hackers and cybercriminals with the intention of causing harm, stealing sensitive information, or disrupting the normal operation of a computer system.

Computer viruses can be spread through various means, such as email attachments, infected websites, or removable storage devices. Once a computer virus infects a system, it can replicate itself and spread to other files and programs on the computer. This can lead to a range of negative consequences, including data loss, system crashes, and compromised security.

Computer viruses can come in many different forms, including worms, trojans, and ransomware. Worms are self-replicating programs that spread through networks, trojans are disguised as legitimate software but contain malicious code, and ransomware encrypts files and demands payment for their release.

To protect against computer viruses, it is important to use antivirus software, keep software and operating systems up to date, and exercise caution when downloading files or clicking on links. Additionally, it is important to regularly back up important data to prevent loss in the event of a virus infection.