Antivirus industry was invented many ways to combat computer viruses. To date, we can distinguish five main approaches to anti- virus security. Firstly, this is an anti-virus scanner. The scanner came into being almost simultaneously by the computer virus. The principle of the scanner is to look at all the files, boot sectors and memory with a chain of detection of virus signatures that is a unique code of the virus. The main drawback of the scanner is the inability to keep track of different versions of the virus. Anti-virus monitors are a type of scanners. But unlike the latter they are constantly in the computer memory and perform background checks files, boot sectors and memory in real time. Anti-virus software-immunizes divided into two types: immunizes that tell about the infection, and immunizes blocking infection with some type of virus. The first is usually written at the end of file (on a file virus) and when you run the file every time it checks for change. Lack of such immunizes just one, but it is fundamental importance: they are absolutely not capable of detecting stealth viruses. The second type of immunizes protects the system from the defeat of any particular virus. To this end, the files are modified so that the virus took them to the already infected. All of the above types of antivirus software do not address the main issue of protection against unknown viruses. Thus, computer systems are vulnerable to them as long as the antivirus vendors do not develop an antidote. Sometimes it takes several weeks. During this time, you can lose all the important information. The most promising area of anti-virus protection is the creation of so-called behavior analysis. They are capable of almost one hundred percent guaranteed to resist attacks by new viruses. This is a program residing in computer memory and hooks various events in the system. In case of detection of suspicious behavior, blocker prevents this action or seeks permission from the user. In other words, the lock is not looking code of the virus, but monitors and prevents its action. Theoretically a blocker can prevent the spread of any both known and unknown (written after the blocker) virus. Although behavior analysis and solves the problem of detecting and preventing the spread of macro viruses, it is not designed to remove them. So, it should be used in conjunction with virus scanner, which can successfully destroy viruses. There are rules for the so-called computer hygiene. These directed must comply with each user. Then spreading viruses will be much less. First in any case, do not open files sent by e-mail unknown to you people. You must check with the virus scanner all floppy disks, compact discs and other mobile media, and files retrieved from the Internet and other public resources. You should carry out a full virus scan of your computer after receiving it from the repair services. Repairmen use the same disks to check all the computers - they can very easily record infection with another machine.