My nano won't restore, it says it can't because "files are being used" Please help me get the "chipmunk's and Beiber" off my ipod!!!

First and foremost, just say no to Beiber

First, close all open apps on your computer and restart your computer. Open only iTunes when it restarts.

Then, I would reset your iPod, probably not needed but I would do it any way. Hold the sleep/wake button and the volume down button until the Apple logo appears. Wait for it to completely start up to where it is ready to use.

Now try and restore. If the iPod was synced with your own computer to put the music on, you can use it to remove it. Usually that is preferred instead of restoring.