On this page of the Internet Explorer 7 Customization Wizard, you must choose the operating system and processor architecture for the computers on which you want to install the custom package.
Select the operating system that you want to use from the list.
With Internet Explorer Administration Kit 7, you can customize and install Internet Explorer 7 on computers running x86-based and x64-based versions of Windows XP with SP2, Windows Server 2003, and Windows Vista operating systems.
You must create a separate package for each operating system that you want to support. To retain settings across multiple operating systems, specify the same destination folder for each package. The packages are saved in different subfolders within that destination folder.
For more information about this stage of the Internet Explorer 7 Customization Wizard, see Stage 1: Gathering Information.