Can't access the dashboard or website

All of the sudden I am having issues accessing my website and dashboard. First I need to explain my set up. My website (let’s call it http://www.example.com) uses WordPress. I wanted to create a subsite that only my salesman could use, so I created a folder for sales and installed in WordPress in the folder to create a subsite. I then password-protected folder. So the subsite is now http://www.example.com/sales.

Everything was working perfectly fine. Then all of a sudden if I tried to access any part of my subsite http://www.example.com/sales I am redirected to a page on my main site http://www.example.com. No matter what page I tried to access on the subsite I am redirected to the same page on the main site. If I tried to access my login for my subsite http://www.example.com/sales/wp–admin to log into the dashboard I get redirected to a WordPress page that says “no update required your database is already up to date” the URL for this page is http://www.example.com/wp–admin/upgrade.php?_wp_http_referer=%2Fsale%2Fwp-admin%2F

any thoughts on what could be causing this issue? I’ve tried changing my theme the twentyten theme. I’ve tried renaming my plug-ins page. I deactivated my plug-ins one by one. I haven’t tried downgrading my WordPress version because I’m not entirely sure how to do that. But any suggestions and help would be greatly appreciated.

Thank you.