I have a few hundred songs on my pre now, and I just added a few more. However, the last couple of times I added new music, the Pre music player isn't seeing them. I know they are in the memory because I can see them when I open the pre as a folder. I'm addding the music when the pre is in usb mode. I use windows media player to sync the music, in the past this has worked fine. Any thoughts please? Thanks!!!