ipod is detected but could not be identified windows 8

HI, I have a Nano i-pod 4th Gen and I have wndows 8. I keep getting the message "ipod is detected but could not be identified" and I have followed all the steps advised, putting i-pod into disk mode, re-installing i-tunes etc, but this does not seem to work. Also have connected my girlfriends i-phone 5 and i-tunes does not pick up that device either but the laptop charges it.

Can you help please?

Cheers