This content is from Secrets of the iPod by Christopher Breen (Peachpit Press 2002)

I regret to report that—except for you, dear reader, and me—nothing is perfect. No, not even the iPod. Whereas it may tick happily along one day, the next day, its menu structure is a mess; it refuses to start up when you're sure it has a full battery; or when it does start up, it displays an icon indicating that it is feeling far from well.

In this chapter, I'll look at the common maladies that afflict the iPod and what, if anything, you can do about them. I'll also examine the iPod's hidden diagnostic screen.
Problems and Solutions

Unlike a computer that can fail in seemingly countless and creative ways, the iPod exhibits only a few behaviors when it's feeling poorly. Following are the most common problems and (when available) their solutions.

The Rest of the Guide

Above links references this great resource for iPod owners who have issues and want to repair their pods themselves. Quite a few solutions to some of the problems that plague iPod users.