What is malware?

"Malware" is a term for any software that gets installed on your machine and performs unwanted tasks, often for some third party's benefit. Malware programs can range from being simple annoyances (pop-up advertising) to causing serious computer invasion and damage (e.g., stealing passwords and data or infecting other machines on the network). Additionally, some malware programs are designed to transmit information about your Web-browsing habits to advertisers or other third party interests, unbeknownst to you.