If its a new server, make sure youve got php support.
If its simply printing your code as html within the browser then its not parsing the document for php.
If your sure youve got php support, make sure your mime types are pointed to use ;
application/x-httpd-php
Other than that I cant think of any other reason why your server isnt processing the scripts. Ensure your php documents have either php, php3 php4 or phtml extensions.
Hope this helps