Hi jusa, first of all i suggest you try another USB port on your PC if you have done this then try switching off your PC plug in your mp3 player then switch on again then your mp3 player should appear as a removable drive in My Computer, if that does not work either then do any other USB devices work in the same USB ports, if no then it is probably the USB/2 drivers that need re-installing, if yes the did your mp3 player come with any seperate instasllation disc which wold have the drivers on it, having said all this it can also depend on many factors, like XP service pack 1 or 2, and what operating system.