My DPN-7000 no longer works as it states that my disc is blank. How can I download operating system onto my compact Flash 4GB memory card. When I look at it on my computer, the file is blank. It was working well before and I also updated it in Nov or Dec 2011. However, I forgot the website to find the update service. Please provide link or file I can download for current OS and maps for Korea. Regards, John Nowell email: janowellkorea@yahoo.com