Executing php.index in directories

I humbly submit this request for help after trying to understand how
to configure Apache (Win XP Pro) to handle index files in directories.
Apache is configured to serve up files from the correct root of my PC
hosted site C:/Program Files/Apache
Group/Apache2/htdocs/[MySite]/htdocs

Althought the directory contains a file index.php, Apache lists the
contents of the directory (*.php icon is '?') instead of executing
index.php Okay, I thought that Apache does not recognize index.php as
a valid index file. Except that further along in my directory
structure, C:\Program Files\Apache
Group\Apache2\htdocs\[MySite]\htdocs\phpMyAdmin\index.php executes
beautifully.

So, Apache and PHP can work together, but there is something about how
Apache handles php files in C:\Program Files\Apache
Group\Apache2\htdocs\[MySite]\htdocs\phpMyAdmin\ and below that was
(accidentally) implemented correctly when I followed the advice of PHP
Project on how to install PHP for Windows. Obviously, I do not know
how to replicate that nice execution further up in my directory
structure.

Sorry for the elementary query, but does anyone have any quick advice
on this to get me up and running?

Thanks in advance.

Farrobo