What's the difference virus spyware malware trojans

Malware: from the words malicious and software, is software designed to infiltrate or damage a computer system without the owner's informed consent. Malware includes computer viruses, worms, trojan horses, most rootkits, spyware, dishonest adware, crimeware and other malicious and unwanted software.

Virus: A computer virus is a computer program that can copy itself and infect a computer without permission or knowledge of the user.

A computer worm is a self-replicating computer program. It uses a network to send copies of itself to other nodes (computers on the network) and it may do so without any user intervention. Unlike a virus, it does not need to attach itself to an existing program. Worms almost always cause harm to the network, if only by consuming bandwidth, whereas viruses almost always corrupt or modify files on a targeted computer

Spyware: Spyware programs can collect various types of personal information, such as Internet surfing habit, sites that have been visited, but can also interfere with user control of the computer in other ways, such as installing additional software, redirecting Web browser activity, accessing websites blindly that will cause more harmful viruses, or diverting advertising revenue to a third party. Spyware can even change computer settings, resulting in slow connection speeds, different home pages, and loss of Internet or other programs.

Trojans: a trojan, is malware that appears to perform a desirable function but in fact performs undisclosed malicious functions. Therefore, a computer worm or virus may be a Trojan horse. Malicious Trojan Horse programs are used to circumvent protection systems in effect creating a vulnerable system to allow unauthorized access to the user's computer.

Adware: The term adware frequently refers to any software which displays advertisements, whether or not the user has consented.

Rogue security software is software that uses malware (malicious software) or malicious tools to advertise or install itself or to force computer users to pay for removal of nonexistent malware. Rogue software will often install a trojan horse to download a trial version, or it will execute other unwanted actions.