I had this same issue. It seemed to work again after I removed the back, reseated the battery back in, but the was a metallic rattle in the inside. When I took off the back fully there was a silver colored metal plate that had come unsoldered. Anyone know what the function of that plate was? 2ds turns on without it in there but need to know if it could cause issues if not put back on. Don't want any hazards.