An infection is a kind of malware that is developed to replicate itself and spread out to other computer worms (look what i found) systems. The most common type of virus is the boot sector infection, which infects the boot sector of a hard disk. Boot sector viruses are typically spread by floppies or USB drives that are contaminated with the virus. Other common kinds of infections include file-infecting viruses, macro viruses, and e-mail viruses.