My sister has an iPod and we have iTunes on our computer. All the songs she had on her iPod were on iTunes, until recently. Now everything she had on iTunes is gone, and we don't know why that happened. Also, she can't add anything else to her iPod or hook it up to her computer or she'll lose all the songs she has in it. What can be done to fix this?

Take the iPod to a technician to reset everything on the iPod and maybe do some re-installations.

Wouldn't doing that erase everything on the iPod?