BuddyPress.org

If you used the BuddyPress Template Pack plugin to add BP support to your theme, the plugin copies over template files to your theme’s directory.

You can remove these template files by deleting these directories in your theme:
/activity/
/members/
/groups/
/forums/
/blogs/
/registration/

Also make sure you have BuddyPress and anything BuddyPress-related deactivated.