I recently had to reinstall windows xp pro on a computer due to some problems with the computer running very slow and freezing up.
I went ahead and did that now Windows Update tells me I need to install Microsoft Windows Installer 3.1 to be able to receive updates again.
I went ahead and did that and everytime I think the download i done when it tells me to restart my computer I do so and when my computer is restarted, its telling me to install it again... I've tried several times with no prognosis!!