I still can't open any PHP file, even by double-clicking. No matter what I do,
You can't open a php file (or in this case a html file too) with a double click in explorer or using the "file open" dialog in your browser.
--> XAMPP is a server, thus you have to use "http://localhost/foo.php" in the browsers address bar.
Additionally we are only able to help:
- if we know the filename and directory where you have stored your PHP file
- and with URI you are using in your browsers address bar.
(the relevant entry in the "error.log" can also help)
BTW:
This is the first exercise in the book PHP and MySQL Web Development, Addison/Wesley press.
Maybe you want start with a simple "Hello World" script from the PHP manual. Just to see how a webserver is working?
Can anyone recommend a book that deals with configuring Apache, PHP, and MySql in detail so I can figure out what is wrong?
You don't need a book about how to configure a webserver. Maybe a book about: how to use a browser to access a file which stored on a webserver.