Hi Thomas i think it is better you can go to a local repaire service guy to identify the root caused: Battery issue/power IC issue/CPU Issue/USB Board. 1. battery issue, it is easy to replace with a battery and fixed it. 2. if it is concern to motherboard, i think it is not easy for you identify it, it maybe need replace with a motherboard. 3. if it is USB Board issue, it will be easy to buy a USB Board. Thanks Jack.
the battery is not easy damage during disassemble, it is better you have warm the battery body a little bit as the glue paste the battery to house body. if the battery is not work at all, you can find a battery for replacement. Thanks Jack.