Well that is a fine kettle of fish isn't it?
Vista won't let me activate MS Reader, so I can't DL any of my Amazon ebooks before they delete them onto my current platform. So all I can do is keep around an old machine with the ebooks on it and I won't be able to reference them from a newer machine.
All I can say is "Amazon, why do you think I'd trust you enough now to purchase anything from you in Mobi format???"
Consumer harming pair of monopolies now it seems, sigh...