Running under Windows Vista?

Is there some trick to getting PHP5 to install properly under Windows Vista? I had a successful Windows 'localhost' installation of Apache/MySQL/PHP about a year ago, and I've been trying to get the same thing up under Vista (Home Premium). MySQL and Apache2 install fine, but I just cannot get Apache to recognise php coding. If I try to run phpinfo() as a "Hello, World!" example, I get the full contents of the source file displayed on the monitor: <?php phpinfo() ; ?> I've made what I thought were the required changes to httpd.conv, and stopped and restarted Apache, but php just won't kick in. Would somebody please hold my hand, and walk me through what I need to do step by step? Many thanks.