A computer virus is a malware that, when executed, replicates by reproducing it self or infecting other programs by modifying them. infecting computer programs can include as well, data files, or the boot sector of the hard drive. When this replication succeeds, the affected areas are then said to be "infected". The term computer virus was a misnomer until it was coined by Fred Cohen in 1985. Viruses often perform some type of harmful activity on infected hosts, such as acquisition of hard disk space or CPU time, accessing private information, corrupting data, displaying political or humorous messages on the user's screen, spamming their contacts, logging their keystrokes, or even rendering the computer useless. However, not all viruses carry a destructive payload or attempt to hide themselves—the defining characteristic of viruses is that they are self-replicating computer programs which install themselves without user consent.