When you logged into your database, where you able to access the wp_usermeta table? I ran into the same issue as you described above and when I went to my database, wp_usermeta said it was in use and not accessible. I had to repair that table and once I did I was able to regain access to the admin area.
You have to edit the .htaccess in the main root director. Add the following code on the line after #End WordPress
AddType x-mapp-php5 .php
AddHandler x-mapp-php5 .php
If you attempted to upgrade wordpress and it did not work and you are missing 1/2 your dashboard, this will also fix that.
