Windows is like a power outlet. You can stick in two-prong and three-prong plugs (i.e. software/hardware). Even plugs of varying wattage. But you try to stick in a fork and it's bound to get fried. Windows (and other OS's) are just trying to support as many different plugs as possible, while preventing access to forks, but someone is bound to try and stick a fork in, nonetheless.
Vista is just and updated outlet (supports higher wattage/voltage), with a nice new faceplate to match your decor. Of course, you have to rewire (upgrade) your house for the new outlet.

Vista is just and updated outlet (supports higher wattage/voltage), with a nice new faceplate to match your decor. Of course, you have to rewire (upgrade) your house for the new outlet.







