Thanks for your help. I'm trying to get http://www.example.com/ working in the browser so http://www.example.com/xampp works (ref page 18 of the Zen Cart book by Goh Koon Hoek) in order to configure the Mercury mail server etc. My files are now set as follows:

hosts
------
# Copyright (c) 1993-2009 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

# localhost name resolution is handled within DNS itself.
# 127.0.0.1 localhost
#
127.0.0.1 www.example.com # for browser access
127.0.0.1 mail.example.com # for mail access
127.0.0.1 example.com # for mercury mail server

The C:\xampp5680-portable\apache\conf\httpd.conf and C:\xampp5680-portable\apache\conf\extra\httpd-vhosts.conf are now configured as recommended by torvista above, but still the error message displayed is "This domain is established to be used for illustrative examples in documents".

My apologies if I'm missing something obvious, but I would like to get http://www.example.com/ working.

Thanks

John