WP admin login issues

I uploaded content from a wp.com blog site to a wp.org site. I was updating the site details and moving around the content when my computer just shut down on me. Now when I try to login this the msg I see when I go to the /wp-admin/

Warning: Cannot modify header information – headers already sent by (output started at /home/content/33/7393233/html/wp-content/plugins/easy-javascript-post-slider/simple_slider.php:13) in /home/content/33/7393233/html/wp-includes/pluggable.php on line 896

How do I fix this?

I tried going back to Godaddy to have them restore from a backup but they were unable to. We even tried troubleshooting the plugin (thinking that might be the problem) but still didn’t work.

Any suggestions would be appreciated!