How to Block the contents in the Site?

To block a site following the instrutions:
1) Go to this directory [c:\windows\system32\drivers\etc], directory may change according to drive used for os installation
2) then hit enter
3) find a file named "hosts"
4) Right click on it and open with word pad.
5) In the last link of the document type the IP* address of yahoo space http://www.google.com/ (Vice versa for other sites)
6) now save it
7) restart the browser if its already running
8) Now try it, It works perfect

IP*: to find IP address of that website Goto start ->Run > type cmd > enter. Now you have a new window on desktop. On that type this without cotes "ping www. yahoo.com"replace yahoo.com with your preferred site and then enter it