Well I can't help you to solve your problem with this particular device. You should check if you can switch from MTP to USB in the players setup. Or maybe it's possible to reset the thing by pressing and holding a button for several seconds while switching it on.
But if you do a search for this player in google, you'll find mostly vicious storys. Most people return the crappy device because of the various problems.
If you want to do yourself a favour, buy an iPod nano or classic. It's simply the best and realiably MP3 device out there.