Hexagon12 said:
I created (and downloaded) the ISO with the Media Creation Tool. The image is not corrupted, because I have a test rig and with the flash drive/DVD it succesfully installed Windows 10 without any errors.
And about running setup on Windows, no, I never actually booted Windows on that computer, I am fixing this computer for a friend, and he says that there was Windows 8.1 64-bit on this system and that I can wipe the hard drive, there is no important data to recover. I am just making two partitions, because the drive is big and can be divided into a system partition and a data partition.