You've probably been surprised at some site with messages like "your computer is not protected" or "your computer is infected". Behind these scary messages (scare) are hiding the real threats. When you accept the recommendation of the site and download the program to the "cleaning" of your hard programinha the malicious suggests that you are with malware - and it's true, he undertook to install - only to remove this malware is necessary "pay for the full version."
The care that you have to have: Obviously, do not trust programs that appear from nowhere and promise to clean your computer from threats. Serious companies will never offer you protection without request.
These following programs say they solved problems of viruses, but are actually malicious software that have the purpose of attacking a PC and say they are security solutions: Security System, Anti-Virus 2010 and XP Registry Cleaner.