Hi, I have a Mac OS X Tiger 10.4.11 macbook, and I'm trying to upgrade to Snow Leopard with the disc information on a SD Card. It tells me to hold down "Option" on startup, and when I do, the only thing I can choose is "Mac" with a picture of the hard drive icon, there is no option for the Snow Leopard Update/SD Card. How do I make it appear? Since there is no SD card slot in my computer, I am using an SD card adapter, and it works perfectly, the problem has nothing to do with the adapter. Please help!