Here, one mainly concentrates on making a Windows 7 Bootable USB drive. For that, you need one USB stick, one err...anyway, you'll get to know.
(1) Download the Windows7-USB-DVD-tool.exe from Microsoft Store (or wherever). If one is facing a conundrum as to which link should be clicked first (or at all), you may click either. I don't know why I do that.
(2) As you may have guessed by its name, this is the software which shall be employed to burn Windows 7 ISO image to a USB stick (the needful).
Note: You must have Administrator privileges on the computer where you are to install the Windows 7 USB/DVD Download Tool. Also, Microsoft .NET Framework version 2.0 or higher is required.
(3) Once you are sure of what you have, install it.
(4) If you have downloaded a genuine ISO from the Microsoft Store, skip steps 5 to 7.
It appears that there are two (possibly more) “navigation buoys” within UDF-formatted ISOs that point to two important chunks of the image called Anchor Volume Descriptor Pointers (AVDPs). The first AVDP is near the top of the image, and the second is in (possibly) the last logical block of the image. From what I have come across (by reading articles), this is to support bi-directional reading.
Ergo, assuming each logical block to be 2048 bytes in size, the second AVDP is -2048 bytes from the end of the file; which is what the tool assumes, doesn’t find it and wouldn’t work.
I suppose ISOs downloaded from the Microsoft Store are comprised in a compatible manner so that the situation would not arise. In order to use the Windows 7 USB/DVD Download Tool with Custom ISOs, you can employ the following software. It finds the AVDP in one’s Custom ISO file and copies it to offset (EOF-2048).
(5) Download isoavdpcopy.exe to do the needful as discussed above.
(6) Arrange a situation where isoadvpcopy.exe and your Custom Windows 7 ISO file are in the same folder.
(7) Open Command Interpreter pointing to that very directory, and type in the following:
< name_of_iso.iso> [Enter]
(8) Launch the Windows 7 USB/DVD Download Tool.
(9) Click on Browse, select the ISO file from its location and press Next.
(10) Click on USB device in Step 2, choose your USB device if it doesn’t pick one for you automatically or whatever else the reason.
(11) Select Begin Copying, hold your patience and that should be it. Hope I helped.