Adware: Adwares are software applications that are supported by advertisements (Advertising Software). It automatically display advertisement when the software is running. It is one of the way a programmer can offer his application at a reduce cost or even for free. Most of the time, a license can be bought to remove the advertisement permanently.

Spyware: Spywares are a progression from adwares. In order to provide the user of adwares with more targeted advertisements, various forms of statistics and information on user's activity on the system is tracked and sent to advertising companies. Sometimes these are done under the hood without user's knowledge and consent. Like spying on your habits and activities on your computer. Thus the term spying software.

Malware: Malware are malicious software that affects the normal functionality of your system. Sometimes, annoying pop up will appear out of no where to direct you to some sales sites. Sometimes emails spams will automatically be sent from your system. Adware and spyware progress to a malicious state if it start to affect the use of your system actively instead of just showing you passive advertisement.

What are Virus,Trojan,Worm?

*Virus is a program to cause damage to computer.

*Trojan is a program which is used to gain access to a computer by installing a program on infected PC to open some backdoor. [Trojans are also known as Backdoors].

*Worm is a program which infects the computers which are connected by some network. Worms slow down the network.