Windows Preinstallation Environment (Windows PE) 3.1 is being released as an Windows Automated Installation Kit (Windows AIK) supplement for Windows 7 Service Pack 1 (SP1). Windows PE 3.1 includes all optional components and language packs. You can apply these optional components and language packs to customize the boot.wim and winre.wim images that are part of the Windows 7 SP1 installation media.
This supplement is optional. If you do not need to modify the SP1 boot.wim and winre.wim files, you can continue to use the Windows 7 RTM tools, including WinPE 3.0, without installing this supplement. You can obtain the Windows Automated Installation Kit (Windows AIK) that was released with Windows 7 RTM here.