There is an easy way to block all users of your Windows-based computer from opening certain websites.  This fix is simple to do, and free… but is also simple to get around.  You can use this solution if you want to block the use of YouTube or Facebook at work.

First, open Windows Explorer and go to c:\Windows\System32\drivers\etc
Open the hosts file in Notepad
After the very last line in this file, enter 127.0.0.1 www.facebook.com (or whatever website you want to block)
Save the file, and test it out.

This fix will work for any browser, and any link to the blocked website.