Since two months I cannot connect the Sandisk clip sport with computer. I went to the seller Kjell & company here in Stockholm. He did something behind the desk and then said, that the mp2-player funtioned. But it did not function, when I came home. I discoved later, that “Musik” did not exist any longer.
A couple things to try or confirm:
Try different USB ports or different computer.
Make sure you are using the cable supplied with the player; others may charge, but do not have the data wires/connections inside.