Hi, after some months not using my mp3 player I wanted to do so again, but I was out of battery. I plugged it with the cable in the USB port of my laptop, as I always did before, but it doesn't charge anymore! There is contact between the laptop and the mp3 player but in the upper right corner the battery symbol stays empty. As soon as I disconnect the player I can't do anything because it has no battery left. What should I do? Thanks in advance for your advice.