WP ADMIN SITE HAS DISAPPEARED

Hi
Yesterday after trying to activate a plugin I received warning messages. I managed to solve 2 of these by deactivating the plugin but the other 2 messages are about something that is not even an installed plugin. Today I cannot open wp-admin all that appears is the 3 remaining warning messages as below
Warning: include_once(/home/anne6829/public_html/dogstrollersplus.com/wp-content/plugins/random-ads/) [function.include-once]: failed to open stream: Success in /home/anne6829/public_html/dogstrollersplus.com/wp-settings.php on line 473

Warning: include_once() [function.include]: Failed opening ‘/home/anne6829/public_html/dogstrollersplus.com/wp-content/plugins/random-ads/’ for inclusion (include_path=’.:/usr/lib/php:/usr/local/lib/php’) in /home/anne6829/public_html/dogstrollersplus.com/wp-settings.php on line 473

Warning: Cannot modify header information – headers already sent by (output started at /home/anne6829/public_html/dogstrollersplus.com/wp-settings.php:473) in /home/anne6829/public_html/dogstrollersplus.com/wp-includes/pluggable.php on line 850

The top 2 also appear on my actual page at the top.

Many thanks for any help
Anne