Why, when I synced my shuffle to my computer, did most of my library disappear?, Why, when I synced my shuffle to my computer, did most of my library disappear?

I gave my Shuffe (v.4) to my daughter, as her Zune has bit the dust. It still had a few dozen songs that I had on it, when she got it. She downloaded the newest iTunes and then plugged in the Shuffle to sync it for the first time with her music. She had over 2,300 songs. While she is aware that the Shuffle only holds 1/10 of that, after her sync, most of her library on her original computer hard drive, disappeared. After this sync, we used (via telephone) Windows Explorer and looked in her Libraries/Music/My Music/Zune folder. It appeared that all of her songs were gone. We then looked in the .../iTunes folder and the only music there was what I had had on the Shuffle when I sent it to her the other day.

Any ideas as to 1. What might have made her library disappear, or 2. Where her songs might be if they are still on the hard drive?

Thanks,

SSG978