VIRUS - viruses are programs that can entry computers or networks in many ways causing incidents that range from simply annoying to high destructive (of information not hardware).

SPYWARE - these are malwares that install themselves on computer with out permission and collect personal data. Spyware can come through non-secure websites, with free software, with viruses.

HACKER TOOLS - these are tools used by hacker to attack systems from remote computers. Can come with other malware such us virus, trojan horses.

DIALERS - these are programs that could deal to a premium rate numbers with out your permission and knowledge. Can cost you LOT OF money.