Title: Antivirus software Content: Antivirus software (or anti-virus software) helps prevent access to a computer system by an unwanted computer malware. Viruses, worms or trojan horses can be used by criminals or mischievous people (called 'hackers'). They can steal information or damage system files. If no antivirus software is installed on the device, hackers will be able to access the information in the computer. ==Types== There are many different types of antivirus software, and many antivirus programs that can be downloaded for free. These free antiviruses usually have some features missing, and the missing features are only available to those who buy the full version. Even still, many free antiviruses today have great virus scanning capabilities and can give people suitable internet security protections without the need to buying additional protections. ==Features== Antivirus software protects computers in many different ways. For starters, most antiviruses offer more than just "virus" protection. They protect computers from all different kinds of malware, like spyware, rootkits, phishing, and ransomware. For this reason, antiviruses are frequently interchangeably referred to as "anti-malware" programs. There are a few more ways that antiviruses protect against malware, but the most used way is through a regular scan of all the data and files on a computer's hard disk. In an antivirus scan, the software will look through every file on a computer, and it will compare each computer file's genetic makeup with the genetic makeup of already-known viruses. If a file has the same genetic makeup as a known piece of malware, it will be flagged as a problem. This is known as signature-based detection, and it is only effective when a malware file has been previously identified and shared with the community of malware researchers who maintain the malware database. Another typical kind of malware detection is through behavior analysis. This is when the antivirus software identifies an abnormal behavior in a computer file or program, causing the antivirus to flag that issue and assess whether or not the abnormality has been caused by malware or by something else. == Problems with antivirus software == Most tests and experts claim that while antivirus software is extremely useful in preventing some cyber attacks, but it is unable to all attacks. That is because once a piece of malware has been identified, hackers know that this malware will be added to the list of already-known viruses, and it will no longer be able to pass through most signature-based detection systems. Also, antivirus software is not completely perfect, and there are more new and emerging threats that mostly sneak by a computer's defenses. Installing more than one antivirus is never a good idea. The two different antivirus software may interfere with each other and causes damage. Sometimes antivirus software sees viruses in files that do not actually have viruses. This is called a false positive.http://www.offlinetalk.com/index.php/topic,106.msg169.html The antivirus software will may remove files from the computer that do not have to be removed. This may cause other programs to not work correctly.