getting 403(Access Forbidden) error while accessing the site through browser

Hi I'm getting 403 error while im accessing my live site through the browser. It was working fine last day. I'm not sure why this error is coming. I have searched a lot about it. These are the solutions I have tried:

1. I have changed my httpd.conf file's configurations from default to :

   <Directory /> #Options FollowSymLinks Options Indexes FollowSymLinks Includes AllowOverride All Order deny,allow Allow from all </Directory>

2. Changed the permission for /var/www/html directory from default to 777

and few more things. But nothing worked. I am not sure what is going wrong.

My server configurations are:

Apache/2.2.29. AWS EC2 Instance.

This is the Error message shown on browser:

forbidden

You don't have permission to access / on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

This is the Error message from error_logs:

[Thu May 21 14:58:51 2015] [error] [client XXX.XXX.XXX.XXX] Directory index forbidden by Options directive: /var/www/
[Thu May 21 14:58:51 2015] [error] [client XXX.XXX.XXX.XXX] File does not exist: /var/www/error/noindex.html

please let me know in comments if you need anything else. Thanks in advance :)