I transfered a lot of albums from my old computer to my Sony NW HD1 but when I now want to transfer new tracks from my new computer following message appears: "Cannot transfer from this computer because the ATRAC HDD contains tracks from another computer. All the tracks from the ATRAC HDD must be deleted before tracks can be transfered from this computer. If you authorize the ATRAC HDD, you will also be able to transfer tracks from other auhorized computers." Do anyone know how i deal with this problem or do I have to delete all my old tracks? Thanks!