I have a Windows 8 PC and my Nikon D3100 isn't showing up on it. It says USB device not recognized. I have updated the USB drivers, but no joy. Sadly, i don't have the disc that came with it.
You do not need the disk that came with it - it SHOULD be recognised as a mass storage device or a camera by the OS.
if the camera is not detected by ANY computer with a known working cable, take it back to the shop.