I trust you have done a "hard reset" on your iPod, the instructions can be found here:
Learn how to reset your iPod - Apple Support
In a nutshell,
To reset your iPod, follow these steps:
- Slide the Hold switch to the locked position and then back again.
- Press and hold the Play/Pause and Menu buttons together until you see the Apple/iPod logo (about six to eight seconds). You might need to repeat this step.
If you still can't reset your iPod, follow these steps:
- Plug your iPod into a power adapter and plug the power adapter into an electrical outlet.
You can also plug your iPod into your computer. Make sure that the computer is on and isn't set to go to sleep.
- Try to reset your iPod again.
If this doesn't bring it back to a state where Windows will find it and identify it as an iPod to iTunes, then you might have bigger problems. You can also take a look in the Windows device manager and make sure it's identified correctly. In my Windows 7 system, it shows up both in the "disk drives" list and in the "portable devices" list, and it's the latter interface that I believe iTunes is using to sync the iPod, restore the factory settings, and so on, not the disk drive interface. Bear in mind that you might need to do the "deep clean" procedure to get rid of and then reinstall the Apple Mobile Device Support part of the iTunes kit, when I did the deep clean, I noticed that that had not been updated when the original 12.2 build got installed by Apple Software Update. Just saying... Good luck.
Note: I was writing this while tt2 was also drafting a reply, so he may have offered some of the same advice.