You can add any such hosts/IP address to your HOSTS file.
Depending upon your release of windows that is, because micksoft chose to remove it as of XP-SP2. MS thinks its a security risk... like trhe rest of windows aint!?
There is a fix to reinstate it
If a site is in your Hosts file, and has its address set to 127.0.0.1 (localhost), that site will not be able to be loaded from the web as 127.0.0.1 is itself.
Your hosts file probably looks like this, if you have one
# 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.
#
# For example:
#
# 102.54.94.97 rhino.acme.com # source server
# 38.25.63.10 x.acme.com # x client host
127.0.0.1 localhost
To block any and as many hosts as you want, add a line like so:
127.0.0.1 www.microsoft.com
127.0.0.1 youclick2earn.com
127.0.0.1 www.persiankitty.com
and so on.
John