There is page of os statistics 2009
. WindowsXP having a leading possition - it's mutch more popular then other operation systems.
The second position take WindowsVista, at first part of 2008 it start to increase using statistics, but it decreasing now.
The third place take Linux and Windows7, the last become popular in very short period of time and going to be more popular very fast.
Vista has a number of new features, and a new interface. Regardless of whether it's XP moving to Vista, or XP moving to Win7 -- those unfamiliar will have a learning curve to learn the new interface, the new features, and
the new methodologies of use, this is based on operation systems statistics for year 2009.
Windows 7 is a version of Microsoft Windows, a series of operating systems produced by Microsoft for use on personal computers, including home and business desktops, laptops, netbooks, tablet PCs, and media center PCs.
OS statistics 2009 showing that Win7 have a great potentsiyal, and will be more used then WinXP.