Today I ran into an issue with one of my DNN sites... I changed site settings and set the login page to one of the tabs which resulted in no access to login page for me and my users...I tried some of the solutions on the web but none of the earlier worked because I had removed friendly URLs host setting.
To get the access back try adding ctl=login to the end of a query string it forces a load of the login dialog eg http://www. mysite.com/default.aspx?ctl=login . If this doesn't work, try this to get around the problem http://www.mysite.com/Home/ tabid/<36>/ctl/Login/Default.aspx (change <36> with home tab id)
If this also doesn't work, John Mitchell has also posted a solution in his blog, where he has created an alternate login page that you can upload, you can view the details here:
Finally last one worked for me...Thanks John