[mc8005]

I'm not exactly sure what's wrong with this media player I bought...The first day I got it, it worked great, now, it won't play anything new I try to load on to it. I know haven't overfilled the (possible) 4gb memory, I'm only at 2.85gb. I loaded a few videos on it when I first recieved it and they worked fine. But nothing I've tried to load since will work. I've even tried deleing and reloading those videos I started with and now THEY don't work either. It's not giving me an error message or anything, it just seems to freeze. Anyone have any suggestions on what is causing this problem and how I can fix it?

By the way, it has a really amazing picture quality AND sound quality compared to other devices I've seen.