When I plug in my. when I plug in my Zen Micro to the PC to chage all i get is the flashing charge

Question

when I plug in my Zen Micro to the PC to chage all i get is the flashing charge signal but the devices does not recgharge. This is the same USB that i have used successfully on another PC. it also wont register on my pc when i plug it in so am unable to orgainze my Zen.