IntroductionComputers are becoming more and more important machines and the uses of computers are becoming more and more varied in our lives. The reason they use a computer for different purposes is because people look for the computer specifications they need. To satisfy people's needs, computers are developing rapidly, but as the use of computer increases, not only the computer is developing, the Internet is developing rapidly. The Internet is now essential in our lives. More than billions of people around the world use the Internet to communicate with each other or get the information they need faster, without any limitations on time or location. This makes the quality of human life more convenient and rapidly improves the network and the Internet. However, there are also downsides to the development of the Internet, usually computer viruses called malware. Computer viruses spread rapidly across the Internet and now pose a major threat to the contemporary information society. Viruses can corrupt computer data, steal private information, or even control your computer. To protect against viruses, antivirus software has been invented and developed recently by many companies. Antivirus software is a program with unique methods for detecting and removing malicious programs. Computer viruses. There are hundreds of thousands of viruses in the world and they are usually designed for a different purpose or purposes. Most computer viruses written in the early and mid-1980s were limited to self-reproducing and did not have a specific damage routine built into the code, but after more and more programmers became familiar with the viral programming, they created viruses capable of modifying data or even destroying it on an infected computer. Middle of paper......computers and various features to help with additional protections. But most of them use the same basic detection methods such as real-time protection, signature-based detection, heuristic detection, and rootkit detection. In antivirus industry, the most important task is to classify known viruses based on their activities, even a single malware program has multiple malicious activities and propagation routines.References http://www.avast.com/en- nz/compare-antivirus http://en.wikipedia.org/wiki/Computer_virus virus history http://csrc.nist.gov/publications/nistir/threats/subsubsection3_3_1_1.html Heuristic virus http://www.pctools. com/security-news /heuristic-virus-definition/ Rootkit http://en.wikipedia.org/wiki/Rootkit Zenny zelster http://blog.zeltser.com/post/1256199682/what-is-cloud-anti- virus Federick B, Cohenhttp https://en.wikipedia.org/wiki/Fred_Cohen