More...Until now, those buying new PCs with Windows 7 Ultimate or Windows 7 Professional have had the option to downgrade those machines to Windows XP. Microsoft had said this option would end 18 months after the release of Windows 7, or with the shipping of Windows 7 Service Pack 1, which entered beta on Monday. Had that happened, those buying machines after that date would only have had the option to run either Windows 7 or Windows Vista.
At least support for SP3 continues until 2014, since SP2 support ends tomorrow.