You need to reinitialize it, which will reload the device firmware and reformat the drive.
http://answers.microsoft.com/en-us/z...8-f5e9d8b00710
But, fix the problem of your PC not recognizing it first. Open device manager, and find the USB hub where the zune is connected and tell us what the error msg is. (Right click the exclamation point.)
And, hard drives clicking indicate a problem but not necessarily a hardware problem. the head is seeking data and not finding it. that could be just corrupt data, or a real hardware defect.