In my view this is really totally unacceptable. If for any reason I need to reinstall the operating system (this is really my choice to do this), then I don't want to be dictated to HOW I should do this. I really have no choice but to run a version of windows at home as a lot of the research I do for my job is windows based and I'm not about to go changing what I do for a living because I want to move to linux (I do actually run linux on another machine). There is NO REASON whatsoever for microsoft to stop me from installing an upgrade version by booting from the disk and then when prompted inserting my full copy of my previous version of windows in and entering the software key that I paid money for.
In fact this is a sales and marketing decision and nothing else, its really quite disgusting they have done this. Luckily I will be needing the ultimate version so hopefully this WILL install in the "classic way", otherwise I will be forced to buy a full copy which is significantly more expensive. I resent that, and much as I doubt it will change anything I just wanted to state publicly that no matter how big a company is or how "important" its product is, it can all end tomorrow if your customers stop buying.