Search, wp-login.php, wp-admin not loading

Hello,

I upgraded to WordPress 3.8.1 this morning, and I cannot get into /wp-admin and the wp-login.php. Have you heard of any similar issues with the update and with the fastfood theme?

We had noticed that the search box was not working before this update, which was 3.6.x, and had hoped that the update would fix this issue, but there still seems to be a sticky wicket.

This is the error I get on wp-login.php:
Fatal error: Cannot redeclare check_password_reset_key() (previously declared in /Public/html/wp-login.php:281) in /afs/umich.edu/groupPublic/html/wp-includes/user.php on line 1637

This is the error I was getting with the search page:

Notice: register_sidebar_widget is deprecated since version 2.8! Use wp_register_sidebar_widget() instead. 

Notice: wpdb::escape is deprecated since version 3.6! Use wpdb::prepare() or esc_sql() instead. in /wp-includes/functions.php on line 2908

Any advice would be great!