bbPress.org

If you cannot access the WordPress admin, even without bbPress installed, then some other change is making your WordPress admin inaccessible. Did you modify wp-config.php in any way? Can you access your WordPress site without getting a white screen?

If you have access to logs on your server, you can find out what Internal Server Error (500) is causing the white screen.

To uninstall, you just need to remove the folder and drop the tables in the database. But with the folder removed, I don’t think your white screen has anything to do with bbPress at all. Unless you modified wp-config.php or any of your template files to incorporate bbPress.

Did you make any changes other than installing bbPress, at or around the same time?

Sounds like you have it installed in the correct place, according to the layout you posted here.