The lifecycle clock is ticking for a number of older versions of Windows.
At the end of every calendar year, Microsoft Corp. pushes more products out to pasture. The company revised its support policy last October so that it now offers a minimum of five years of "mainstream support" (measured from the date of a products general availability) for all its business and developer products. (The time period is shorter for consumer, hardware, multimedia and Microsoft Business Solutions wares.)
At the end of mainstream support, business and developer software customers have the option of purchasing up to two years of "extended support." After that time, users need to become self-supporting, relying on online help and knowledge base articles if they need assistance.
To find out which products will lose support, go to the full article.