1. First you will need to go on a computer open iTunes and plug your iPod connector cable into your computer.
2. Then simply hold the home button for about 5 seconds and while still holding it plug it into your computer.

This unlocks the iPod because corrupt data puts it in lock down mode and from here, if you’ve previously backed up your iPod/iPhone, just click restore and it will put everything back on your iPod/iPhone.

And if you haven’t backed up your iPod/iPhone before you can just sync with your iTunes or put your music, videos, apps, and contacts back on manually.

To do this just go to where it says iPod on your iTunes and just click manually manage music.