Definitions from Wikipedia (and others):
Malware or Malicious Software is software designed to infiltrate or damage a computer system without the owner's informed consent.
A computer virus is a self-replicating computer program written to alter the way a computer operates, without the permission or knowledge of the user.
A worm is “a program that self-propagates across a network exploiting security or policy flaws in widely-used. services”
zombie - a computer under remote control after a successful malware or manual attack.
Spamming is the abuse of electronic messaging systems to send unsolicited, undesired bulk messages. While the most widely recognized form of spam is e-mail spam, the term is applied to similar abuses in other media [ … ]