Virus is something irritating in the computer world. Starting from small problems like shutting down programs unexpectedly to crashing the entire system, virus has its role. Virus is a computer program that can enter into a computer without getting noticed. The main stream of virus spread is through Internet. There are many forms of viruses like ad ware, malware, spy ware etc. Viruses are more vulnerable to Microsoft Windows platform because many virus programmers switched there interest to it since windows grabbed most of the market in early 90's.
Mac OS has a unix based file system which is different from Windows so it is less prone. Only 63 virus has been listed which can attack MAC operating system. There are many software which are used to protect our system from virus. Many anti virus softwares are available in markets. Symentec's Norton is one of the anti virus. We have many of these software like Kaspersky, AVG, Avast!, Mcafee, eset NOD32, etc.
Lets see how virus software works. We have seen anti virus softwares gets regularly updated. When it gets updated signatures in the software changes. Signatures are released by anti virus companies. A signature is generated and released when a new virus spreads. This is how a anti virus software generally works.
Anti virus software also has its own disadvantages. Some softwares makes the computer slow. It can sometime do false analysis and delete a file. But have a virus scanning software is very good for a computer.
