Hello Tonywh,
Even though the update that is not installing is the OGA update, its deployment and installation is supported by Windows Update support:
http://support.microsoft.com/gp/wupdSome people have found that the OGA update fails if your computer's task scheduler service is turned off. How to check:
http://www.theeldergeek.com/task_scheduler.htm
For great advice on all topics XP, visit http://www.annoyances.org/exec/forum/winxp