Final answer:
A computer virus is a malicious software program that can spread and cause harm. It can damage files, steal information, and take control of your device. Symptoms include slow performance, crashes, and unusual error messages.
Step-by-step explanation:
A computer virus is a malicious software program that is designed to spread from one computer to another and can cause various harmful effects. It is a threat to your security because it can damage or destroy files on your computer, steal personal information, and even take control of your device. Computers can catch a virus through infected email attachments, downloads from untrusted websites, or by connecting to infected external devices. Symptoms of a computer virus may include slow performance, frequent crashes, unusual error messages, and unexpected pop-ups.