Here are the dates when support will end for PCs running Windows XP and Windows Vista without the latest service packs:
Support for Windows Vista without any service packs will end on April 13, 2010. To continue support, make sure you've installed Windows Vista SP2.
Support for Windows XP with Service Pack 2 (SP2) will end on July 13, 2010. To continue support, make sure you've installed Windows XP Service Pack 3 (SP3).
