You have to login as administrator, then find user using "user list". In the last section (administratoin) you will see option for deleting users with or without his posts. Unfortunately you have to delete users one by one.
It is quite complicated procedure and I don't recommend to delete these users directly using SQL. But if you must, don't forget to:
- delete the record from table users
- delete from tables subscriptions, forum_subscriptions, online where user_id is his id
- delete all records from table posts where poster_id is his id
- delete all topics which first_post_id refers to post of this user
- fix moderators in table forum, if the deleted user was moderator
- at the end delete all files in cache folder
If this forum is new, I suggest to install it once again. This time don't forget about installing extensions like pun_stop_bots or something.
If you want to contact me quickly - send e-mail, not PM.
<?php $t='<?php $t=%c%s%c; printf($t,39,$t,39,10);%c'; printf($t,39,$t,39,10);