Hi, Some computers with Windows XP, Windows XP Service Pack 1 and Windows XP Service Pack 2, have the problems that when you are updating the system, some updates are uncompatible with another update or with a software. And there updates that are unused by the system.
In this case, its better to reinstall the system, and when you are going to update in windows update option, click in Personal update, NOT I FAST, the webpage is going to look which updates can use in your computer, also aditional software, and drivers that you computer use, select them first the esencials, them de aditional updates. Look that there are some updates that you have to install separate.
And then finish the updates, your computer are updated, remember to switch off the automated updates in the control panel.
Well I expect to explain the errors of updating, and could be the problem of your computer. Bye