Check the httpd.conf file and ensure the declarations for PHP are included:
# For PHP 5 do something like this:
LoadModule php5_module "c:/php/php5apache2.dll"
AddType application/x-httpd-php .php
# configure the path to php.ini
Personally, I've always put the php.ini file with the rest of the *.ini files in Windows. Alternatively, use Linux - any flavour will do. I've been using RedHat/Fedora/Ubuntu/Debian for quite a few years now, and every installation has been error-free.