An ISO file, short for International Organization for Standardization, is a type of disk image file that contains the contents of a CD, DVD, or Blu-ray disc. In the case of Windows 7, an ISO file is essentially a snapshot of the installation media, which can be used to create a bootable USB drive or virtual machine.
Your ISO file is too large or corrupted. Switch to a streamlined, stripped-down Windows 7 Lite ISO.
These "exclusive" builds usually feature: