You can determine which version of Zen Cart you are running by using either an FTP program (like WinSCP) or your cPanel's file manager to view the file /includes/version.php.

You'll also need to understand what PHP (and possibly mySQL) version you're currently using. Create a file named check_version.php that contains:
Code:
<?php phpinfo ();
Place that file at the root of your store's hosted file system and then use your browser to navigate to www.yourstore.com/check_version.php. That output will tell you which PHP version is active and a bunch of other information. Remember to delete that file once you've retrieved the information.

You'll need to review the database "credentials" in your two configure.php files (/YOUR_ADMIN/includes/configure.php and /includes/configure.php), making sure that they match the credentials configured in your web-host's cPanel.