I struggled for a good solid month to get IIS/PHP working in Windows 7 with no luck. I ended up uninstalling IIS, undoing all of the system changes to enable PHP and installed XAMPP Instead. took 3 minutes to download, 2 minutes to install. at the end of 5 minutes, I had a working PHP/MySQL testing server.
See our "Setting up a Testing Server for Windows" Tutorial on the learning resources page for inforamation on setting up XAMPP.