Hello all, here's an update...
I have a testing account on my domain. I've set its IE security settings for Intranet Zones to Low, and granted the Everyone group NTFS Read + Read & Execute + List Folder Contents on the site's root folder (which is inherited by all the subfolders & files).
I access the site by typing in 'http://suspenses', so no periods in the URL or whatnot.
If I try to access the site under this test account, I am prompted for credentials a number of times, then returned a 401.3 error.
The default page that I attempt to access does not call any graphics, stylesheets, SSIs or what not. It is a static ASP page with no server-generated content whatsoever.
What I have learned, though, is that by trying to access an ASP file, I am prompted to enter my credentials. However, if I try to access only an HTML page, BOOM! No problems there.
Could this be a permissions issue with ASP.DLL or some other system file?
My WINNT folder has the Everyone group listed as having Read + Read & Execute + List Folder Contents, as does the IUSR_<computername> account.
Past that, I have not found any useful information through Microsoft or Google searches.
If anyone can contribute some info to my pursuit of a seamless, authenticated application, please do!
As always, thanks to all who take the time to read