” Microsoft has ruled out putting Internet Explorer 9 on Windows XP, leaving millions of PCs open to Mozilla and Google browsers providing hardware-accelerated rich-internet.
Ryan Gavin, senior director of IE business and marketing, said Microsoft would not put IE9 hardware acceleration features in the current version of its browser, IE8, or back port IE9 to older PCs running Windows XP… “

16th September 2010

Microsoft: IE9 will never run on Windows XP • The Register

More  http://www.theregister.co.uk/2010/09/16/no_ie9_9_on_windows_xp/