1>>Follow below steps.

1). Go to Start > Programmes > Accesories

2). Then Right click on Notepad and Run
it as administrator.

3). Now open host file by clicking on File > Open
and locate to following address C:WINDOWSsystem32drivers etc

4). Then just below # 127.0.0.1 localhost paste folowing code # Blocking Facebook
127.0.0.1 login.facebook.com
127.0.0.1 http://www.facebook.com
127.0.0.1 apps.facebook.com
127.0.0.1 blog.facebook.com

5). Now save the host file and done.

6). Open any browser and try to open
facebook.
It won’t open.
If facebook
opens then you might have done
somthing wrong.

Enjoy.