I was going through my closet and found my Dingoo A-380 I got a couple years ago. I was excited to use it, so I plugged it in to the USB port on my computer and... nothing. I shrugged it off thinking that it just couldn't charge from my USB port for some reason and plugged it in to the USB charger on my surge protector. It turned on and worked fine. Later I unplugged it to plug it into my computer and put some new files on it, but as soon as I unplugged it, the screen went black. Wouldn't turn on, nothing. Plugging it back into the charger turns it on immediately and it works fine. What's going on?