[MrGoodtunes]

If you can get good stereo out from the USB (headphones, FM transmitter, and/or multi-media speaker system), then it's a good bet USB's okay. Still, pocket fuzz can mess it up. Also, the chrome paint can chip off the band near USB socket, get into the socket, and short out crucial connection(s). With good bright lighting and a magnifying lens, you can use a small soft bristle brush to clean debris out. Oh, and have you tried checking and unchecking the box here?...

Start > Settings > Connections (tab) > USB to PC