Computer wont recognize a plugged in mp3 player

Neither of my laptops will recognize my sport clip. They will charge it by usb but its not listed on connected devices or on media player for sending it files. This started about three weeks ago when I tried to add songs. Before that it worked fine. I tried to update using the driver update download but since the laptop wont see the device, it wont update any drivers. How can I fix this?

Did you change the power cord to a generic one?