I just purchased my 1st Mac, mbp 15 4G, just love it, but am light years behind everyone else here on MacRumors. I will be brief (in my pathetic ignorance), and hope a few kind souls will take pity on me. What do I do about security (I really only plan on keeping my many pictures, music, and home videos on here, and will probably only download the same from iTunes at this time), and when I upgrade to Snow Leopard, do I need to back up what's already on my mbp? Thank you for your mercy!