Sorry you're still having problems; - Just so that I know exactly what your config is, are you running your Apache/PHP/MySql as part of XAMPP or WAMP or have you installed each module seperately and configured them to work together yourself?
After changing the httpd.conf file and the MySql user back to super-user (root) did you restart Apache/MySql? (You would need to have).
Some users report having problems with database tables after adding the AddType application/x-httpd-php .php directive: - this from the phpMyAdmin documentation:
It is possible to configure Apache in such a way that PHP has problems interpreting .php files.
The problems occur when two different (and conflicting) set of directives are used:
AddType application/x-httpd-php .php
In the case we saw, one set of directives was in /etc/httpd/conf/httpd.conf, while the other set was in /etc/httpd/conf/addon-modules/php.conf.
The recommended way is with AddType, so just comment out the first set of lines and restart Apache:
It may be quicker in the long run to remove whatever Apache, MySql and PHP (& phpMyAdmin?) you have from your machine, and download XAMPP afresh; - you should be up and running in twenty minutes that way. If you need a run-through for that option, there is a post HERE that might help.