Copying a website to test server doesn't work.

Folks,
I've copied a working website from a production server to a test server.
I've set up IIS to what I think should work and here's what I notice:

If I directory browse, I can see all of the files.
If I try and run an .HTML file, it works fine.
If I try and run an .aspx file, it says file not found even though I can see
the file in the directory browse. I even tried to double click on it from IE
and it says file not found.

Anybody have any thoughts?

It's almost as if IIS won't let .aspx pages be run.

I've got .Net 2.0 on the machine so that can't be it.

TIA - Jeff.