Hi,
there are many reasons why the source code is displayed. Here is a short list of what you might need to check:
1) put php.ini to your windows/winnt folder
2) make sure that engine=On is set in php.ini
3) copy php4ts.dll to your system/system32 folder
4) copy all dll's in the dlls folder to your system/system32 folder
5) Make sure that the following lines exist in your httpd.conf
when php is installed in c:/php (zip package, not the installer. If you used the installer then I'd suggest to uninstall it and uncompress the zip package to e.g. c:/php)
Apache 1.3.x:
LoadModule c:/php/sapi/php4apache.dll
AddModule mod_php4.c
Apache 2.x:
LoadModule c:/php/sapi/php4apache2.dll
Apache 1.3.x and Apache 2.x:
AddType application/x-httpd-php .php .phtml
AddType application/x-httpd-php-source .phps
Hope this helps you a little bit 🙂