These settings can typically be set at the server level (for all php scripts running on the server) with the php.ini configuration file or at a directory level (using .htaccess files). Sometimes the latter is not possible, as there is a setting to disable such overriding of the core php settings.
To do it in .htaccess just add this line to the .htaccess file:
php_flag register_globals off
To change it in php.ini look for "register_globals" and change the value between 0 and 1.