When you use the Internet Explorer Administration Kit (IEAK) to do a Quiet-mode Internet Explorer 4.01 Service Pack 1 (SP1) reinstall, the following not-so-quiet message is issued:
Setup has detected that the newest versions of Internet Explorer components are already installed. To exit Setup without making any changes, click Exit. To reinstall the current version of Internet Explorer, click Reinstall.To shut it up, add the following registry entry to each computer you intended to quietly setup:
where ReinstallFlagQuiet is a type REG_DWORD. A data value of 1 will make it behave.