I have downloaded the ISO from Microsoft's Volume License Service Center multiple times. I have burned many disks, and also tried using the ISO with VirtualBox. I always get the following message part-way through the installation process at the point where it says, "Getting files ready for installation" (which comes after "Copying files"):
Windows cannot install the required files. The file may be corrupt or missing. Make sure all files required for installation are available, and restart the installation. Error code 0x80070570.