Welcome to the Zen Cart forums! If you haven't been continually updating your site since 2007 (around the time that Zen Cart 1.3.8a was released), your site is living on "borrowed time" due to underlying changes made to PHP (the language on which Zen Cart is based) over the past 9 years.

You don't say what version of PHP is currently being run for your site, but anything over PHP 5.2 is going to wreck havoc (at a minimum) or cause your old-ZC-version site to error-out due to those PHP interface changes.
https://www.zen-cart.com/content.php...o-run-zen-cart

In the future, it's best to start a new question as a new post so that your question doesn't get lost in a thread's prior discussion.