I have seen that a lot of people visit this site when searching for:
Handler "PHP_via_FastCGI1" has a bad module "FastCgiModule" in its module list.
So, here's how to solve this:
- Go to Control Panel -> Programs and Features -> Turn Windows features on or off
- Scroll to Internet Information Services -> World Wide Web Services -> Application Development Features
- Turn on CGI
- Wait a bit
For more information how to configure PHP on IIS visit Installation on Windows systems on php.net.