A. We talk about OEM versions of NT, but what is OEM?
OEM stands for Original equipment manufacturers and are basically the large computer companies like Compaq, Dell who get special versions of operating systems and applications that are potentially tailored for their machine hardware. For example special versions of NT exist for OEM's which can support more than the standard 4 processors.
OEM's have access to special tools like the OEM Preinstallation Wizard (Opkwiz.exe) for Windows 9x to help define installations, applications. I wish I had OEM status :-)