PHP settings in server

I am hosting my site on a windows server. Recently, I switched to a new server. In the control panel, I came across the setting for PHP:
Version 5.2.6 or 4.4.7 and run as CGI application/ Fast CGI application/ ISAPI extension. I don't understand what to choose? All I know is to create database/tables and use PHP to read & write to them. My site administrator is not very helpful in these matters. Any guidance with explanation would be welcomed.

generally, most people run PHP as an extension (ISAPI extension), and I would suggest using the latest version of PHP (5.x), unless for some reason you need to use PHP 4.