Many times in schools, colleges & offices surfing some sites like orkut,etc are banned !
* Open the folder C:\WINDOWS\system32\drivers\etc
* There you will find a file named HOSTS* Click on the file and press SHIFT and now right click on it .
* From the right click menu select Open with .* Now, File>>Save !
Now, open your web browser and try openning www.xyz.com , it will not load !
To unblock sites just do the opposite !
Keep visiting