Mp4 digital player keeps turning off

Ok, I bought an MP4 player the other day from ebay and was so excited. But after a while of playing with it, it shut off. I turn it on again, and several seconds would go buy and it would go back off. I tried charging it over night, I tried the sticky thread of how to remove a memory hack, but those seems to check out just fine. Also, I think it has to do with the button presses, because you could watch a full tv episode without it shutting off and that doesn't use many button presses to watch. But it would shut off pretty early when playing a game, which requires a bunch of presses.

So, in summery, my mp4 player shuts off after several seconds of play time, and I would like to ask you fine people if you know how to fix it.

If you need to know what it looks like...

the ebay page for it