Install this, but first this and this and then that.
Today I had to do some maintenance on Windows NT 4 server. I basically needed to install the latest NT service pack on it. If any service pack had been installed, I think it was just the first one (the latest is 6). The service pack installer was downloaded using a Windows 2000 workstation also on the same network.
Once I started up the service pack 6 installer on the server, I was told that it requires at least Internet Explorer 5. I don't really understand why-- perhaps it needed a more recent 'wininet' library to download the service pack files. The currently installed Internet Explorer is good ol' 2.0 (which gets installed with windows NT 4).
So I fetch the Microsoft Office 2000 CD which has the Internet Explorer 5 installation files. As I start to run it, I get the error that it at least needs NT service pack 3 in order to install.
So in order to get service pack 6 installed onto a plain-jane Windows NT 4.0 server installation, you have to install (in this order): at least NT service pack 3, Internet Explorer 5, then service pack 6.