Proclave, I am having the same problem as jacquelinechen. My site is also being hosted by GoDaddy and the problem started around the same time. My site is being hosted on a Windows server.
GoDaddy’s suport pointed me toward the web.config file but were unable to help troubleshoot the code.
I renamed web.config to web.config.disabled. When I tried to get back to the admin page it gave me a 404 error.
Any other ideas?