Hi,
> If I go to my 'c:wamp\www' directory and double click index.php
A php file does not launch by double-click. We must open it in a browser.
In this case c:\wamp\www\index.php is the homepage of Wampserver ('http://localhost/')
Never modify the contents of c:\wamp\www\ or modify the files that are there. You can only add a folder, for example: c:\wamp\www\mysite\ to put your site into.
On the other hand, for web applications, mainly for Joomla and others, you must use a VirtualHost, as with all web hosts:
The need for Virtual Host---------------------------------------------------------------
Documentation Apache -
Documentation PHP -
Documentation MySQL -
Wampserver install files & addons