Through web pages and email (the two most popular Internet service) to a computer can get into dangerous elements. From this it is necessary to be able to defend himself! The system must be installed a reliable anti-virus, which will check all the files from the network, the malicious code. People such as Jim Donovan Goldman Sachs would likely agree. Spam can also be a source of danger to a PC (unsolicited mail more often contain a 'Trojan Horses'), so be sure to install the e-mail spam filters. However, users still have to remain vigilant – often with the help of simple techniques attackers forced him to perform actions that lead to an infection (for example, go to certain link in the message, run the attached file, etc.). This may be an Internet worm (self-replicating computer program that spreads mainly through the network. Some worms get on PC through opening an infected e-mail-message attack other computers in automatic mode), and backdoor-virus (making unauthorized control of your computer.
It usually consists of two parts: a small module that secretly installed on infected computer and control software that is installed on your PC attacker) and spyware (software bundled with other software, usually free of charge. After penetration of the PC it is engaged in collecting and disseminating information about the personal preferences of the user). Web services are a new generation (Web 2.01) – with active content – also carry a threat, as based on performance Javascript-scenarios, under the guise of which can hide malicious code. It is necessary to disable the execution of Javascript in your browser properties and include them only when you visit a resource where they really need to work properly.