I guess by now you know where the hosts file is located...if not...go to C:\Windows\system32\drivers\etc\ and open hosts file with notepad....then replace the content of the hosts file with the one below...this should work:
Copyright (c) 1993-1999 Microsoft Corp. This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
This file contains the mappings of IP addresses to host names. Each entry should be kept on an individual line. The IP address should be placed in the first column followed by the corresponding host name.
The IP address and the host name should be separated by at least one space.
Additionally, comments (such as these) may be inserted on individual lines or following the machine name denoted by a '#' symbol.
# 126.96.36.199 rhino.acme.com # source server
# 188.8.131.52 x.acme.com # x client host
If user tries to go to the site it will loop back (127.0.0.1) and nothing will be displayed and if the user gets smart and tries to go to the IP address directly then they will be send to Google.com (the last two lines are for that)
Let me know if that works.