This simply trick will explain how block the unwanted dart websites .This is helpful to avoid +18 sites from children
Steps:
1] Browse C:\WINDOWS\system32\drivers\etc
2] Find the file named "HOSTS"
3] Open it in notepad
4] Under "127.0.0.1 localhost" Add 127.0.0.2,
5] Done!
-So-
127.0.0.1 localhost
127.0.0.2 www.blockedsite.com
-->www.blockedsite.com is now unaccessable<--
For every site after that you want to add, just add "1" to the last number in the internal ip (127.0.0.2) and then the add like before.
IE: 127.0.0.3 www.blablabla.com
127.0.0.4 www.blablabla.com
127.0.0.5 www.blablabla.com
etc