So, I'm trying to learn how to work with DNN (5.05.00 if I am seeing this right), and while trying to configure Active Directory, I ended up disabling all authentication types... and now, while I can register still, I cannot log in to any previous accounts regardless of superuser status... even host and admin.  Is there an easy way to re-enable this?  Going in to the Authentication table didn't help.  Changed it to True, and admin still can't log in.  :(

Well, I went into the Authentication table and set IsEnabled on DNN, to True. Didn't seem to help. I took your advice and changed DNN_Enabled to True as well... no such luck. I also went into DesktopModules and changed the FolderName for Account Login. That didn't seem to work either. I'm at my wits end here. DNN is definitely not the "easy to use" system I was led to believe. When I try to log in, it just tells me Login Failed. I know for a fact I'm using the right password. I can request my admin password, and I copy and paste it and it doesn't work. Host doesn't work. The new user I registered as didn't work once I logged out of it. Nothing. I'm thinking at this point I should probably just scrap this install. I appreciate the help. I'll probably give it a couple of days in case anyone has any other ideas for me try, but I am really thinking DNN is not for our organization at this point.

I'm not sure how you disabled the DNN Standard authentication but this is what I did to recreate the problem and how I fixed it....

1. Disabled DNN Authentication under Admin->Extensions (this writes a SettingName to the Portal Settings table called DNN_Enabled and gives it a value of False)
2. Closed IE and ReOpened it. Logged in with my AD user. All is good.
3. Closed IE and changed the value for DNN_Enabled to True.
4. Launched the site and went to login. Only one option to login (AD) appears.
5. <Scratches Head>
6. Tries <Ctrl>-F5. No difference.
7. Close IE, Kill the application pool in IIS, and browse to C:\Windows\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files and remove the site.
8. Restart the Pool and relaunch IE, go to the site, and both login options are there.

If this doesn't work for you let me know how you disabled the authentication types so that I can try to work backwards from there. Don't give up on DNN. If I gave up on it everytime I've made a huge mistake I would've quit about six years ago. Take it as a lesson learned. Personally, I always have a "Test" install somewhere for when I want to try something new. If it goes sideways I just restore the backup and try again.