Mp4 digital player keeps turning off

Ok, I bought an Mp4 player and I received it a couple of days ago and I was so excited. But after a while of playing with it, it just shut off. Turn it on again, play it for a few seconds, it would shut off. It kept doing this and after a while I got to charging it on my computer. The battery indicator said full before I charged it and after. It still did the shut off and thing. I did the sticky on this board that says how to remove a memory hack but it shows up that it hasn't been hacked. Charged it up again while I slept last night, so it got atleast 8 hours of charging time, but when I tried again, still, shuts off after a several seconds of playing with it. Anyone out there know how I might be able to fix this problem? Also, if you need to know what the mp4 player looks like:

The ebay page