Oh, the webs we weave when we practice to deceive.
Three of us have tried to drop the hint to Joan that since she did not purchase most of the music on her iPod she is lucky that any of it plays at all. However, as you have observed, the hint is not getting taken. She is still complaining about her one legitimate song not playing when thousands of illegitimate songs do.
The solution, of course, is to reformat the iPod using the iPod Updater utility. The DRM will switch to her computer and all her ripped from CD content and legitimate downloads will play fine. She will be able to happily add playable content to her iPod from then on. BUT, the 'borrowed' content will be gone.
In the interest of not being harsh, let me point out that there are ways to obtain digital content that is both free and legitimate. Every Tuesday the iTunes Music Store gives a way free music, usually two tunes. Many introductory television series also offer one or two programs free at iTMS. News podcasts are free, too. Outside of iTMS, there is plenty of free digital content at Amazon and Veoh.