Songs grayed out after new computer

We got a new computer running windows 7. Both iPods ( my 5th gen iPod touch, and my sister's 1st gen nano) are on the same account. When I plug mine in, all my songs are there, but hers are all grayed out. She only has about 60 songs, but I think the problem might be with the source, all my songs are from cd's and a few iTunes downloads. Her songs were downloaded from frostwire on our old computer. The songs are on her ipod, but what will happen if she tries to add more songs?

via iLounge Forums http://forums.ilounge.com/ipod-nano/278221-songs-grayed-out-after-new-computer.html