Editing the 'default front page' base URL
Have you tried the below changes in your settings.php and .htaccess?

 /sites/default/settings.php

$base_url = 'http://www.example.com'; // NO trailing slash!


and

.htaccess

  # Modify the RewriteBase if you are using Drupal in a subdirectory and
  # RewriteBase /drupal


Try using this.