Most of these spywares are installed without your permission on your computer. Antispyware scans system memory, registry, hard, and removable drives for a variety of spywares like annoying ad-wares, data-mining scum-ware, key-loggers, trojans, premium number dialers, browser hijackers, Surveillance programs, tracking cookies, worms, malware, P2P, nukers, browser helper objects, downloaders and other tracking components that gather information.