Sometimes we face the White Screen of Death(WSOD) without an error message. White Screen of Death happens due to several reasons. Some of the common WSOD that we face are while making changes in configuration or while running the security updates. If this happens while updating the module, the entire site might face WSOD. WSOD would even stop the bussiness of a site. So this is a major issue from the client /SEO perspective. If you want to fix the WSOD, you need to first identify the error. If you are facing a WSOD, then read on to know more about its causes.
Here is the first step for debugging a WSOD error
Go to index.php and add the following lines after the php open tag
error_reporting(E_ALL); ini_set('display_errors', TRUE);
error_reporting(E_ALL); ini_set('display_errors', 1);
these error reporting options will be helpful to displaying the errors.
Use this link for getting more details : http://drupalwsod.com