Microsoft has confirmed that users of the new Windows 7 will be able to downgrade to either Vista or XP. Downgrade rights will be open through the company’s PC partners, including HP. This will allow users that are more comfortable with Vista or XP to downgrade their operating system at no cost. Large businesses may also not want to change their operating system, especially if certain staff members will be using older versions of Windows.
The rumored target date that Windows 7 will launch is in October. It is also rumored that downgrade rights will be available from October until an undisclosed date. It is also likely that users that choose to downgrade to Windows XP or Vista will still have the ability to access Windows 7 upgrades.
Users would be able to access these upgrades through the Windows 7 Upgrade Option program by doing a clean install of Windows 7. Also, consumers that purchase Vista equipped PCs from June 2009 to January 2010 can upgrade for free to Windows 7.
Read: [ZDNet]
It is great i have window xp and now i can switch to window 7 i am waiting for that window i have used vista also but there is so many problem so that I turned back to window xp but I think that window 7 will be better that vista