iPod nano 6th generation restored, then failed

I have an iPod Nano 6th gen I haven't used for a couple of years. I charged it, and the battery indicator showed a full charge. The screen displayed a "Use iTunes to restore" message. I connected the iPod to iTunes (latest version on Windows) and received a message that it restored successfully. Restoring the unit erased it, so I started loading music on it. iTunes showed the transfer about 90% complete when I got an "unknown error" on iTunes and the iPod disappeared from iTunes. Now iTunes doesn't recognize it, and my Windows PC doesn't see it. Based on a recommendation in another thread, I went to Device Manager to try updating the Apple Mobile Device USB Driver, but it doesn't appear under Universal Serial Bus controllers. I've tried different cables and USB ports, but all the iPod does now is flash the Apple logo, and occasionally the "Use iTunes to restore" screen. So is my iPod kaput?