Sorry, but we have no intentions of providing official support for any Windows based web-servers.
You could try using an Apache solution (something along the lines of WAMP, but that's explicitly only intended for development purposes).
If you want to use IIS, you'll have to write a config file yourself.
Ensure that you are correctly rewriting requests to the index.php as the .htaccess file does. FOSSBilling uses virtual paths and will not function if requests aren't rewritten in that way.
Keep in mind, not every single request should be routed through the index.php file like that. Our NGINX and Apache configs should both be accurate points of reference.
