Don’t panic.
Changing table prefix manually requires changing it in multiple places in database and if you have lost your admin access, then it can be regained by adding the values in the database. Some more experienced can tell you this in detail.
And BTW are you also using WP in the same database with wp_ as the table prefix or without it?
i have different databases for BB and WP..
now i want to have bb and admin back
is there any way in modification in config sign
or can i transfer my db in new user table
I think you have installed bbPress again by using wp_ as a prefix
take a backup and try this :
change to bb_
and then open bb_usermeta table and see if the bb_capabilities of your user (check with user id) is a:1:{s:9:"keymaster";b:1;}
via phpmyadmin
if you have got the admin access back now, then you can delete tables starting with wp_
Hope that helps