Computer Viruses A computer virus is a program that spreads copies of itself from one computer or disk to another.
Viruses can spread quickly and have become a significant problem in the computing community.
Viruses vary in sophistication but usually spread surreptitiously and are designed to hide very well. A virus can do significant damage. Some slow the operation of a computer, while others may erase files or reformat entire hard drives. Some viruses are designed as relatively harmless pranks, causing the computer to show a message or to beep. Even these seemingly innocuous viruses are damaging, degrade computer performance, and waste your time to remove them.