You have deleted all your data without a backup. Seems to me there is no solution.
Last resort is to build a time machine or ask your webhost. If you ask nicely they may retrieve a backup for you … ?
If the posts are indexed and cached by Google, you could retrieve them all and re-enter them…
Check with your host to see how often they do backups for you.
Some premium hosts do daily and weekly backups which would save you.
no I didn´t delete the bbpress data. only the wpdata.
I reinstalled all, but still no admin panel.
Users can still register and posting are still there and possible to make.
is there no other way?
Have a look in your mysql database with phpmyadmin at the bb_usersmeta table for your user (whatever ID that is, which you can get from the bb_users table). If you find the row that has the meta_key column of bb_capabilities, you’ll probably find the meta_value is:
a:1:{s:6:"member";b:1;}
If you change that to:
a:1:{s:9:"keymaster";b:1;}
You’ll find you’re an admin and can see the admin panel.