C250 usb connection not recognized

My c250 is not longer recognized by my computer when I plug in the USB cable. Nothing is listed under my computer and there is no ding when it is connected or disconnected.I am using Windows XP. I have tried connecting to 3 different computers with no luck.

what does it say on the screen of the player? does it do the same thing without a battery?

give 866.sandisk a call and see if you can get it replaced under the warranty.