Why is my iPod classic unable to connect to my USB port?

I'm wanting to download music onto my iPod and was able to do it only yesterday but as I try and connect to my computer today, it's saying that my device is unknown and is not able to connect. My computer is Windows 8 and I've tried everything to sort out 'Code 43' but nothing seems to work. I've also changed the cable several times and seen if my iPod is still able to charge from a socket which it is. I'm not sure if this has something wrong to do with my iPod or my computer but any help will do. Thank you xx