If you use the Internet browser "Opera", then you have the opportunity to deny entrance to the sites using the settings of the program.
Go to the menu item "Tools" located in the top of the browser".
In the opened window select "Advanced", then click "Blocked content". In the opened window, enter the addresses of sites to which you want to deny access.
For users who are well versed in Windows, there are other ways. In this case, we are interested in the “hosts” file located in the directory at the following path: “C:Windowssystem32driversetc”(for Windows 2000 the path to the directory is “C:WINNTSystem32driversetc”). To quick search the file, press the key combination Win+R, in the opened window, copy the directory path specified above.
Open the file “hosts” using Notepad. In the open text we are interested in the line where is the word "localhost". In this line, we see an example - "127.0.0.1 localhost". Furthermore, in order to block, for example, the site "Vkontakte" or "Odnoklassniki", or any other site, just go to the end of the document and enter the following:127.0.0.1 www.vkontake.ru, 127.1.0.1 www.odnoklasniki.ru or any other site, access to which should be banned.A little explanation: the numbers on the left - nothing but the internal IP address of your computer, right — the name of the domain to which you are going to deny access.
In order for the changes to take effect, you want to save the file (with administrator privileges), then restart the computer. The next time you try to go to blocked sites, the browser will ignore a connection, and page load is interrupted.
If the user you block sites know what "hosts" is and why you need it, you should set a password to the folder in which it is stored. For this there are many programs that you can find on the Internet.
Most children learn early enough to disable such prohibitions parents. If you want to be more confident in the safety of your child from harmful content, you should use firewalls and firewalls.