Somebody correct me if I'm wrong or miss a step...........First, backup your old data in iTunes. On Windows version of iTunes, the backup wizard will be under File - Library - Back up to Disc. You then need to de-authorize your iTunes account on your old computer. And finally, on your new computer authorize your iTunes account and login to the iTunes store (this might be one step instead of two). Now you should be able to sync without any loss of data.