I haven't used my playbook in a while and I dusted it off to see if I could install some android apps. It seemed to charge fine the first time, but now it won't. It must be taking some power from my computer, though, because it stays on while it's plugged in. It just says it is Unable to charge battery with connected source. I've tried other chargers with the same result. Is there any reset I can do to fix the issue?