Cannot Find Development Site Anymore


I have a development site in a subdirectory of my live site. It has been working fine since I made it (following this guide: )

However, I went to log in today after a week of not using it and it is now showing my live site stating "404 Error". I get the same error when I try to log into the administration panel of the dev site.

If I log in via FTP, I can see the subdirectory is still there and the admin php file is still named as before.

Any ideas what else I can check?

**Edit: Not sure why the link isn't working. I followed the CS-Cart guide