When I ran the PHP windows installer, it still left a LOT of installation steps undone. Basically, it was 90% useless and 10% pure irritation...
You'll need to make sure that either CGI or ISAPI (your choice) handling of PHP scripts is enabled for the particular virtual host and/or directory. Most of this is outlined in the PHP Manual
Also, is that a typo? PHP v 5.3.10? Did you mean 4.3.10, hopefully?