[Ashish Kumar (Ashfame)]

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