A computer virus is a type of malicious software program (“malware”) that, when executed, replicates by inserting copies of itself (possibly modified) into other computer programs, data files, or the boot sector of the hard drive. When this replication succeeds, the affected areas are then said to be “infected”.
Viruses can cause extensive damage to data and computer systems. They can delete or corrupt files, alter or destroy data, and even take control of a computer system.