WordPress crashed !

I am unable to open the site, even as an wp-admin. Here is the error shown in the browser:

Warning: require(../../../wp-load.php): failed to open stream: No such file or directory in /home/prasadm/lms.technoeschool.in/wp-content/plugins/simple-ajax-chat/simple-ajax-chat-core.php on line 4

Fatal error: require(): Failed opening required ‘../../../wp-load.php’ (include_path=’.:/usr/local/lib/php:/usr/local/php5/lib/pear’) in /home/prasadm/lms.technoeschool.in/wp-content/plugins/simple-ajax-chat/simple-ajax-chat-core.php on line 4

Please give me a clue. I am desperate.
Thanks.
–pm