Your clues solved my issue. I clicked the link to the Professional ASP.NET 3.5 book and read part of chapter 1. It gave me the idea to put the site under wwwroot. So I copied the Release folder to wwwroot, made the appropriate directory change in IIS and completed the other security settings outlined in your book.
Now the site works perfectly! I can enter either http://localhost/
in my brower and I'm brought to the home page with the theme applied and can then go to the login page with the theme applied and browse the rest of the site.
Any further thoughts on why the site didn't work correctly when under C:\BegASPNET but does when under wwwroot?
Now to try publishing the site to my web hosting provider.