Still not working: PHP4 running on server, but not on dev box (SuSE 9.2)

Hi folks, Been through the suggestions offered here, have compared the config files on my development box and my server, and I'm still stuck. To recap, I set up SuSE 9.2 with Apache 2 and PHP 4.3.8 on a server and it's running fine. When I installed, I included Apache and PHP from the very start. Then I took an existing desktop 9.2 box, added Apache 2 and PHP 4 to it via YAST later. I can't get PHP to respond to function calls. Apache is serving up static pages fine, but it's not recognizing PHP. I've compared /etc/apache2/httpd.conf, default-server.conf, and php4.conf (in conf.d), and they're basically the same. (The two differences are that the document root is different on the two boxes, and I've got virtual hosts set up on the server. Neither should affect this problem.) I've done no manually editing or modifying, other that the two differences just mentioned. I don't know where to turn next to troubleshoot this; it seems like Apache on the dev box doesn't see PHP, but how to test? How to tell it? Thanks, Whil