That query should work.
phpMyAdmin is something most webhosts will provide you with - it's a separate program so it's not part of UBB.Threads. It's handy because you can visually see the database. It's available at
www.phpmyadmin.net and it's free. <img src="https://www.ubbcentral.com/boards/images/graemlins/smile.gif" alt="" />
So were all the groups deleted? Try this query to see.
SELECT * FROM w3t_Groups
