Worst plugin

The worst plugin I’ve ever downloaded, it broke my function.php file, now my website is not working and I don’t know how to fix it cause I’m not a PHP professional. After I downloaded this plugin my website started giving me this message:
Notice: wp_register_script was called incorrectly. Scripts and styles should not be registered or enqueued until the wp_enqueue_scripts, admin_enqueue_scripts, or login_enqueue_scripts hooks. Please see Debugging in WordPress for more information. (This message was added in version 3.3.) in /home/advandz0/public_html/bluebirdnewdemo/wp-includes/functions.php on line 3897 Notice: wp_register_script was called incorrectly.