iPod won't sync with iTunes
I recently moved all of my music onto an external hard drive, but now when I plug in my iPod, it won't sync with iTunes. iTunes recognizes my iPod just fine, but no matter how many times I click the Sync button, they don't sync up. I've bought new songs in iTunes and they're not syncing to my iPod, made new playlists, etc. How can I get both of them to match up again? Why isn't it syncing? Can anyone help me out?
(I'm using iTunes 11 on Windows Vista, with an old style iPod)
iPod classic, Windows Vista