Block any web site in windows XP

You can use the Windows 'Hosts' file to accomplish this, here's how:

In Windows XP, the hosts file is found here:

C:\Windows\System32\Drivers\etc\hosts

Double click the 'Hosts' file and select "Notepad" or “TextPad”
from the list of programs to open it with.Once you have the
hosts file open in Notepad, you will see an entry such as:

127.0.0.1 localhost

To block a certain web page from loading, add the following:

127.0.0.1 www.abc.com

Your Hosts file will now look like this:

127.0.0.1 localhost
127.0.0.1 www.abc.com

Once you are finished, go up to 'File' and click 'Save'.