The same thing is happening to me :S Im really mad. heres what happened:
I was on my way up to the ski hill and had just finished watching a movie. When I went back to the movie menu, none of the pictures came up beside the movie titles, so i tried to play one. It didnt work. It ended up that none of them worked. So i was thinking I would just turn it off hten turn it back on. I turned it off, but it never came back on

No, it still wont turn back on, and whenever I connect it back to the computer, it doesnt charge (that I know of) and the software doesnt recognize it. but if I go to the device manager, it says it is connected and working properly :S
So it just basically wont work. Does anybody know what I should do? I have tried everything I can find. Now I am thinking that I might have to send it back to MS. Please reply.