Did you ever figure out a solution? I'm having the same issue with my Lenovo S8-50 tablet - won't charge, won't turn on. I'm not sure if you've tried this yet, but I actually tried plugging the tablet into my laptop's USB port and windows told me there was a power surge on the USB port. At that point, my wireless USB mouse stopped working at well, which makes me think Windows just disables all USB devices when something like that happens. I think it also might be an indicator that the USB port on the tablet is shorted out so it's trying to draw too much current. Anyhow, I think the solution might be to replace the tablet's USB port.