Before you get flamed, I'll try to answer your questions. Users are ... users of the computer, that will be setup automatically. Those accounts will exist when the installation is finished without needing to create them afterwards. --> you don't "need" to specify a value, you can create a user. --> if you don't specify, no additional user will be created -"adminisrator" and "guest" are MS buid-in accounts. You can also deactivate any of them if you want. OOBE is the "Out of the Box Experience, it's the part where you create the users and set an Internet connection to register and activate your XP. If you use "skip OOBE", no activation possible, even later. The list of installed "Language Groups" controls which user locales, input locales, and system locales are available. These resources include code pages and fonts. Localization will define things like how numbers are shown, money units and other. If you ever installed any flavour of Windows, you might probably vaguely remember about all these formalities you have to fulfill. It's not hard for him, he just assumes people wanting to tweak a Windows Install CD know about that Windows installation at first. And as the program is free, he might as well concentrate on the work it does.