The idea of computer viruses emerged long before personal computers. In 1959 an American scientist L.S Penrose published in the journal article about the self-replicating mechanical structures. The simplest model of two-dimensional structures capable of activation, proliferation, mutations capture was described in this article. In those days computers were huge, complicated to use and extremely expensive machines, so their owners could be just big companies or government computing and scientific research centers. But soon the access to computers got millions of people of different professions, social backgrounds and mentality. Not surprisingly that then it was the first prototypes of the modern computer viruses. Conditions for the virus are becoming more and more favorable. Range of available personal computers for ordinary user grew, in addition flexible 5-inch magnetic disks appeared stiff, rapidly developed local networks, as well as technology transfer files using the conventional switched telephone lines. All this contributed to the implementation of the third most important conditions for the development and spread of viruses - individuals and groups involved in creating viruses began to appear. The main thing that unites all the virus writers - is a desire to stand out and express them, even in such endeavor. In everyday life, such people often touching look demure, who can't say boo to a goose. All their vital energy, hatred and selfishness the world find an outlet in the creation of small computer scoundrels. There are a lot of different types of viruses. 90 years have been the most fertile time for computer viruses. If before computer viruses have evolved mainly extensively (i.e., increased their number, but not the qualitative characteristics), today due to improved data transmission technologies we can talk to the contrary. To replace the primitive ancestors had cleverer and crafty viruses witch are much better adapted to new environmental conditions. Some methods of combating viruses cannot cope. Today virus program is not limited to damage files, boot sectors, or playing innocuous tunes. Some of them are capable of destroying the data on chips motherboards. At the same time masking technology, encryption and distribution of viruses amaze sometimes even the most seasoned professionals.