The php code you suggested is exactly what I have done to test my php/apache/mysql installation:
<?php
phpinfo()
?>
I get absolutely nothing, zip, page is blank...
All I get each time I launch it with a browser (Firefox or IE) is the pop up window asking me if I want to open this file with a browser or save it. If I launch it with a browser I loop back to the open this file with a browser or save it pop up (loop-de-loop, and around we go).
I have double checked the Apache service and it is working just fine (apparently).