Help me my mp3 died (samsung yp-u1z)?

I was trying to copy some files a friend gave me (i also use my mp3 as a thumb drive) and windows went stupid so i was forced to restart my computer. Then when i tried to access my mp3 again it told me i had to format it, which i did since i had other copy's of my songs. now my computer won't even regester it's there and when i try to turn the mp3 itslef on it loads to 20% and starts again. I'm pretty sure formatting it wasn't the problem since the user info that came with it recomends formatting as a quick way to remove the data but i've really got no idea wat happened. My sisters (same model) also died like this a while ago, though i don't know what she was doing when it happened.