Anonymous Access to ASP Pages not working

Hi

A freshly installed IIS on my Windows XP SP2 does not allow anonymous
acces to the default ASP file (localstart.asp). I just used default
configuration for installation, which enables anonymous access. But
when I load http://localhost I just get a login box. A simple
index.html placed manually for debugging purpose loads without login
prompt.

I am testing the same thing on a Windows XP (w/o SP2). ASP works for
anonymous access like a charm.

As I am not familiar with IIS and ASP I would appreciate any hints to
solve the problem.

Thanks in advance.
Daniel Frey