I have updated the site to Drupal 7.4 up from Drupal 6.14. During the update I have deleted the custom modules to make the upgrade process smoother and get rid of all the bloat for a fresh start. As a result, the site looks a bit different but all the content is still there, and loads faster. :) It is bare bones right now but in time I will customize the theme and add some modules that I wanted to keep back into the site. Having the site on Drupal 7 will also make it easier for me to maintain.
Oh and user registrations are now re-enabled.