I am trying to find a way to clear cached HTTP BASIC credentials from within  IE 6.

A little background:

A website that I am trying to use uses HTTP AUTH to collect
username/password information, then verifies that information
programmatically against a database to allow access to restricted
portions of the website as well as display the appropriate information
for my user account.  I changed the password for this account and now
cannot gain access to this site through Internet Explorer 6.  Attempts
to access the site through another browser (I used firefox
successfully) do succeed as I am then prompted for a username/password
combination (through HTTP AUTH).  My best guess is that their scripts
are flawed in that they do not transmit an HTTP AUTH invalid response
to the browser and only display "password incorrect" to the user
(thusly, IE does not know that it's cached credentials are invalid and
does not prompt for the proper username/password pair).  Ideally a fix
to the site's interface would be in order (getting it to send the
proper headers in response to an invalid username/password pair), but
this is for a large hosting company and I think that convincing them
to re-code their site would be a monumental effort, so I thought it
better to research clearing the cached credentials so that I might
simply re-enter them.

Every attempt to research this on my own has led to endless
instructions on clearing cached form username/password pairs however
this is not the information I need.  I specifically need to clear the
HTTP BASIC information and cannot find anything on it, not even
through Microsoft's knowledge base.

There is a chance that the site is using a cookie to identify you, and
when that doesn't work it simply gives up instead of prompting you for
a new password.  Have you tried deleting any cookies from that site?
Check in c:\documents and settings\<<your user name>>\cookies

I know it's not a cookie because 1) I cleared out the cache 2) I
killed *all* cookies and 3) It does request HTTP AUTH information when
logged into from another browser.  I'm pretty sure it's IE caching the
username/password pair for the HTTP AUTH in some hidden mystery
location.

Try the following and see if it helps
1. Goto Tools->Internet Options->General Tab and Delete Cookies
2. Goto Tools->Internet Options->General Tab and Delete Files
3. Goto Tools->Internet Options->Content Tab and Clear SSL State
4. Goto Tools->Internet Options->Content Tab and click on Auto
Complete. In the Auto Complete settings dialog: Clear Forms and Clear
Passwords.

I figured out how to clear cached passwords:  It's in the registry
under "Protected Storage System Provider".

However in doing this I uncovered a new problem, which is that now IE
is not requesting the HTTP AUTH information for *any* sites which
request it, I am simply denied access to any sites protected in this
manner.

I have been unable to find any references to this sort of issue within
MS's knowledgebase.

Suggestions?