iPod Classic must be connected to a High Power USB2.0 port at the back of your PC, so that the communication between the iPod and the USB Host controller would be smooth.
Do not connect your iPod to the USB port at the front of the PC or use any USB hub, and while syncing or Restoring your iPod, disconnect all other USB devices except the mouse and keyboard.
So iTunes freezes and hang your PC if it can't communicate with the USB Host Controller, to get the iPod logical ID.
A way forward, is to do a Hard Reset as below
- After charging till full charge, at least 2 hours (preferably 4 hours)
- Toggle the Hold switch, make sure you dont see the red mark when you do the next step
- Reset the iPod -> Press Menu and Center button simultaneously for about 10 secs till the Apple Logo comes ON
- Then release the buttons
- Select your preferred language.
Here is the Apple support Article on the 5Rs
http://www.apple.com/support/ipod/five_rs/classic/
- Put your iPod into Disk Mode
- Connect the iPod to a High Power USB 2.0 port at the back of the PC, and never to the front USB port or any USB Hub.
- Disconnect all other USB devices, except the mouse and keyboard.
- Launch iTunes and wait a while for iTunes to recognise it.
- Restore the iPod software .
It may help, if you can provide these info, to be of any assistance,
- Which version of iTunes are you using?
- What is the iPod firmware number as shown in the iTunes summary page?
- When was the last time you sync the iPod Successfully with no problems? (any Software update snce then)
If you are lucky, the Hard Reset and use correct USB port will solve your problem, else the other causes are time consuming and better resolve by the Apple Genius.
Have a nice day!