How Do I Reinstall The Windows Installer
xphelpandsupport.mvps.orgAlthough Microsoft have a redistributable download of the Windows Installer 3.0 available it cannot be used when Windows XP Service pack 2 (SP2) has been installed. The reason being that SP2 already has the Windows Installer 3.0 software added and, because of file protection, would not allow the Windows Installer file to be replaced.