I know this is an old post. but just in case if somebody stumbles on this post just like me. You need to register the asp.net framework on iis in order to get aspx files running.
go your framework version directory under windows folder using a command prompt. usually it will be like this
start -> run -> type in cmd and click the ok button.
then enter the following
This should do. The 'v2.0.50727' above is the version of the framework.