Ipod won't recognize music

I recently got a used 7G 160gb ipod classic. First time I synced it with my iTunes, it caused my iTunes to start freezing up. So I restored my ipod classic through iTunes. I was able to sync all my songs, however my iPod doesn't recognize them. They are taking up memory but my iPod says there's no music. I've tried "soft restore" by toggling the switch and holding down menu and select but it still does not read the music. Help please?!