I just changed a new installation to use AD for authentication, which at first seemed to work ok, but I can no longer login as Host or Admin, although i can log in as a normal user, using my active directory credentials.  I added a user called HOST to the AD, but that didn't help. 

Anyone have any suggestions?

It's a new install, so i suppose I could just re do it if I have to.

Been there, once, so you have my sympathies ...

If you are in mixed authentication, try this link on your site with your virtual directory if you have one:

http://yoursite/yourvirtual/Home/tabid/36/ctl/Login/Default.aspx

(I think you can use any valid tabid here? Tab 36 is/was? the home page for a default install.)

If your site is purely in windows auth mode, you might want to change web.config just temporarily to mixed mode so you can set an aAD ccount up as an admin and/or SU. Once you're logged in as host via the login form, add your AD account to the administrator's group.

If you have db access, you can try flipping the "issuperuser" flag to 1 on your account in the users table, I recall that I have had this work on a test site but I can't vouch for the safety of doing this. Mitchel's scripts are awesome, by the way.

Once you're in as host you can also add domain\user accounts using Host, Superuser accounts - this was actually how I was able to get into a site we were moving, but I'd set up a domain account as superuser before we moved it. When it came up, nothing else worked but this did, and a good thing, since I didn't have db access to recover the passwords with the scripts. Under that AD account's context, I reset the host and admin passwords and after that they then worked in forms and mixed mode. Something to do with synchronizing the asp_net and dnn user tables, I guess.

Good luck and keep trying,
Roberta