If you have not messed up your Database
Grab a backup now
http://www.zen-cart.com/content.php?...atabase-backup
Then make a folder and upload a ZenCart fileset
Make a new DB
run zc_install to activate the install using the new DB
Use phpmyadmin to import your DB Backup
Re-run zc_install and upgrade DB only

You should then be ready to test