I picked up a pristine used disc the other day, and when I put it in my dvd player it says 'loading' and just stalls there. I exchanged it for another copy and got the same results. Neither my Phantom Menace nor my original trilogy discs have this problem. I use a Pioneer 578A which, to be honest, has been giving me a bit of trouble as of late. Anyone have any info/ideas on what I can do?