There is a simple way by which you can block any site from being accessible from your computer. There is a file called “hosts” located at
C:WINDOWSsystem32driversetc. Now open that file in Notepad. This file is used to map domain names with IP addresses, locally within your computer. So whenever you type a domain name (say google.com) in your browser, the browsr first checks if the domain entry is in this “hosts” file. If not present (in most cases), the browser will lookup external servers.
Now the trick, if you want to block google.com, assign the domain name google.com to the ip 127.0.0.1 (127.0.0.1 is the address of your own computer, commonly known as ‘localhost’) or assign it to any other value such as 127.0.x.x.