If you have only installed Apache and PHP for Open-Audit, and not for anything else, then
uninstall them, and download the latest version of Xampp from the above link.
Install Xampp (The only thing I tend to change is the default installation path, which defaults to C\:xampp I tend to change it to C:\Program Files\Xampp)
If prompted, allow exceprions for port 80 and port 443 through the Windows firewall.
Go to your newly installed xampp installation using the link ...
http://localhost/xampp and set up the Apache and MySQL security from the Security link.
Copy the Open-Audit files to C:\Program Files\xampp\htdocs\openaudit (you will need to create the openaudit folder)
Run the setup program for openaudit using this link....
http://localhost/openaudit Everything else should be covered in the FAQs section on this website.
Let me know if you encounter any problems.