The curse of php files forcing themselves to download and not display normally on your localhost
When you want to change your PHP version (like from 4 to 5) you need to put in your local .htaccess file the line:
AddHandler application/x-httpd-php5 .php
This works fine on a web server, but when applied to your localhost it causes your browser to try to download the .php file as oppossed to display it as normal.
I went mental for a few months and completely stopped web scripting because MAMP and my localhost refused to let me see my local web pages. I thought for a while it was something to do with MIME Types, but I could find no conclusive evidence to support this.
Jay from RebuildTheRobots randomly discovered this when upgrading from PHP4 to PHP5.
Remember: Don’t despair. There is always a solution.