http://web.archive.org/web/20130910115920/http://www.microsoft.com/en-us/download/details.aspx?id=24
или прямая ссылка:
http://web.archive.org/web/20130731094839if_/http://download.microsoft.com/download/d/3/0/d30e32d8-418a-469d-b600-f32ce3edf42d/WindowsXP-KB936929-SP3-x86-ENU.exe