Ok, found a backup from 2 days ago, dropped the database and restored from there, all working again.

Weird.

When I hit that link I got a file not found message from mediafire.

Cash,

I was able to see the image in the provided link. Please try again.

Actually even I got the same screenshot today, when I go to the login page after enabling the option(mentioned below) in the Advanced Settings in the Admin page.

Enable the site to run as a private network. This will not allow non logged-in users to view any site pages other than those specifically marked as public.

• Restrict pages to logged-in users