Why cant windows vista play older games like for windows 2000,XP?

vista has a hard time just keeping itself alive ... let alone hardware or software ...

Why cant windows vista play older games like for windows 2000,XP?microsoft word download

Because Windows Vista is NOT ready for primetime yet. If your not ready to deal with all the incompatibilities and problems, then you should upgrade your computer to Windows XP!

Why cant windows vista play older games like for windows 2000,XP?internet explorer download internet explorer

Because Vista is new and just like other OS with older software its not always compatible. It may be eventually when they release a patch or work out the bugs from Vista. Or they release new versions of games to be compatible with new OS. If you lucky the game will create a patch to make it compatible with Vista but they will most likely release a newer version.
Because its newer and better and faster and more productive and more advanced than the older Windows.
Just so you have to go out and buy new programs. Its Microsofts way of making the customer spend money.
You can try the compatibility mode in Vista that is similar to XP where you can make Vista "run the game as XP" operating system. right Click on the game icon and select properties then select compatibility mode.