Reset, Restore, and Reinstall are the Reduce, Reuse, Recycle of the Apple iPod.
These three terms seem self-explanatory, but seeing as they are Apple's seemingly most common solution, I thought it might be nice to carefully explain to Old People what these words really mean.
RESET This will be the most common "R." When your iPod freezes, or does something it's not supposed to, resetting your iPod will be your first step. RESETTING your iPod is like unplugging and plugging it back in—and it won't cause you to lose your data. Always RESET before you RESTORE.
RESTORE This will wipe your iPod clean. RESTORE will restore you iPod to factory settings, removing your music, media, and personal settings. The implications of RESORING your iPod are a total pain in the behind, because you have to re-load all of your material. It is, however, extremely effective.
REINSTALL If your iPod is corrupted, or just really needs a leg up, you might need to REINSTALL your software. This is also likely to cause the need to add music to your iPod again and reconfigure your personal settings. This will, however, yield positive results, most of the time.
So? The lesson here is to RESTORE with caution.
For specific instructions on how to do all of these things (and more!) with your iPod, visit www.apple.com/support/ipod.
iPod Troubleshooting Assistant, Apple