http://windows.microsoft.com/en-us/windows/help/what-does-end-of-support-mean
Support end dates
Here are the dates when support will end for PCs running Windows XP and Windows Vista without the latest service packs:
Support for Windows XP is ending on April 8, 2014.
Support for Windows Vista Service Pack 1 (SP1) ended on July 12, 2011. To continue support, make sure you've installed Windows Vista Service Pack 2 (SP2).
Support for Windows Vista without any service packs ended on April 13, 2010. To continue support, make sure you've installed Windows Vista SP2.
Support for Windows XP SP2 ended on July 13, 2010. To continue support, make sure you've installed Windows XP Service Pack 3 (SP3). For more information, see Learn how to install Windows XP Service Pack 3 (SP3).
Peccavi, June 2013