Hello,

A better news group would be the ASPNET new group. Anyway, it's been a while
since I have done a web app as well, however, if my memory serves me corret
you need to look at the web.config file.  You need to set the authentication
mode to "windows".  I believe that is the default.  The other thing is you
will need to set the security on the Virtual Directory in IIS so that it is
not allowing Anonymous Access.

Control Panel | Administrative Tools | Internet Information Services
Right click on a virtal directory | select properties
Select Directory Security Tab
Click Edit
Uncheck Allow Anonymous Access

After doing this, users should get prompt to login and they will need an
Windows User Account.

Hope my memory has not failed and this helps you out.