Microsoft Caves to Opinion: Extends XP Availability to 2011
"Windows 7 Professional and Ultimate customers will have the option to downgrade to Windows XP Professional from PCs that ship within 18 months following the general availability of Windows 7 or until the release of a Windows 7 service pack, whichever is sooner, and if a service pack is developed," Microsoft said in an email after changing position from the original 6 month deadline.
Learning curve, compatibility and scalability: These are the reasons that companies fear losing XP – that and it will cost them money. As far as I am concerned companies can keep Windows XP for a thousand years, continue to live in the dark ages and go out of business because of it. Home users should be smarter.
Windows 7 will be better than Vista; Vista is pretty darn good already. With 2 service packs out, most (not all) of the original problems with Vista have vanished. Home users face only 2 out of the 3 problems: learning curve and compatibility. For learning curve, Windows Vista and 7 have a Welcome Center with a full compliment of written information and video demonstrations. There are also many videos on Microsoft’s site for learning Vista. The videos are good and will help most people learn what they need to start using Vista or Windows 7.
Compatibility is a tougher problem. Some hardware and software will not work with newer operating systems. This happens because newer operating systems have added features and functions not supported by older hardware and software. Often there are workarounds; sometimes not. Manufacturers of the hardware and software that run on the Windows platform should also be culpable for updated software drivers. Built-in obsolescence is an unacceptable reason for incompatibility.
Whatever you think, downgrading to Windows XP 1 to 2 years from now is not the answer.

