The term "malware" is short for malicious software, and is software that's been developed specifically to cause harm to computers. Malware is usually installed without the computer user's permission or knowledge and it infiltrates the computer causing annoyances to the user and damage to the system. Malware is a general term that refers to a variety of different types of intrusive, hostile or annoying programs, and includes computer viruses, trojan horses and worms.
A computer virus is a form of malware that can replicate itself and infect a computer. A virus has the ability to distribute itself from one computer to another and therefore spreads easily. For example, viruses spread between computers when users send files over email or the Internet, or on removable devices such as cds and USB drives. Computer viruses also proliferate over network file systems such as those found in offices.Checkout Virus Listing
A Computer Worm, like a virus, can replicate itself but the main difference between a worm and a virus, is that a worm does not attach itself to an existing file or program, and can spread over a network without any action from the user. Worms spread due to flaws in the security of the target computer. By attacking vulnerabilities in the operating system of a computer, worms usually cause at least some damage.Checkout Worm Listing
Trojan horse, sometimes referred to simply as a Trojan, is a harmful type of software that looks useful and legitimate to the user, who is usually tricked into installing it, but instead of performing the function it describes, it allows access to the user's computer system. Such malware can be really annoying and can change the settings of the system, displaying uncontrollable pop-ups, advertisements or toolbars in the web browser.Checkout Trojan Horse Listing