Can't login after 4.0 update

My blog is self hosted http://www.ecommnow.com/blog I updated to 4.0 from within my dashboard and right in the middle of the update, it booted me out completely. After that, it will not let me log back in, I keep getting the white screen. I am not that experienced with WordPress, or coding. Please help!

After searching for Can’t login after 4.0 update, I have followed every recommendation in all the threads, including manually replacing all the files in the wp-admin and wp-includes folders, as well as the ROOT files, like wp-settings.php and the like. I did all that and still get the white screen after logging in. I also renamed my theme as suggested and nothing. I tried changing my password by entering my email in the Forgot password? section (several times), but I won’t even get the email that allows you to change it. I’ve called tech support at my hosting Verio and they couldn’t find anything wrong. The guy suggested I try to get help here.

I use this blog for my business posting at least once a week. But as I said before, I am not a coder. I use BackUpBuddy, but I can’t login to revert to the last back up. Can I manually install 3.9 and hope to correct it that way? Please help!