Steps to create a bootable ISO from a USB drive:
Install ImgBurn. You can even get a portable version of it, just search for it.
Plug the bootable USB into the computer
Click on the "Create image file from files / folders" button on the home menu.
In "Sources" browse to the USB drive.
In "Destination" choose where to save the final .iso image.
Go to the "Advanced" tab on the right and then "Bootable Disk".
Check the box "Make Bootable Image" and then, in the "Boot image" box browse to...<Too long, click to read the rest>
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