If laptop does not recognize any mp3 player, what should do?

Hello,
I have a habit of listening to songs in my mp3 player, every time I am traveling outside. Everything was working just fine. Last night, I plugged my mp3 into my laptop to download some new songs. But, my PC was notifying me that the “USB device is not recognized”. Then, I tried to plug it in other USB ports but it still failed to work. Then, I reinstalled the USB driver on my PC. Again I got a failure. I don’t know why it is happening.
Moreover, the entire play lists in my mp3 player vanished, after trying to connect it again and again. It’s a very bad thing for me. What should I do know? Can anybody help me?
Thank you
