500 Internal Server Error on /wp-admin

I left WP logged in over the weekend. Woke this morning and tried to edit the article I was working on and could not save or publish (greyed out). I exited out of the webpage and tried to login to wp-admin thinking I was just logged out. I then get an internal server error.

The actual wordpress blog loads fine. However, I cannot access /wp-admin.
I have disabled all my plugins through phpMyAdmin (described here: http://wordpress.org/support/topic/500-internal-server-error-wp-admin-only)

At the bottom of the error page this also shows: “Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.”

Please help!!