Nano won't respond to anything. I've tried charging via multiple computers and multiple outlets and I've tried using all combinations of power, home, and volume buttons together. I've been greeted by nothing but the same black screen. There is no response from the computer when the iPod is plugged in (doesn't show up in My Computer or in iTunes). Basically, I want to know what is most likely to need replacement at this point. It could just be the battery, but I would expect it to power on when plugged in. This leads me to believe it would be a failed motherboard, but I have no way to test that. Nothing online (that I've been able to find) describes any part of what I'm interested in. TL;DR: Black screen, no charge, doesn't register on computer. What needs replaced?