I am a noobi and not too bright. I am trying to change from windows 7 Ultimate on an Acer aspire 5742G and unable to get the USB to boot.
I have finally got the file on the USB but I cant save the boot option change in the BIOS.
OK, I finally got it in the Bios, I had to select the security and disable the boot lock I am now wiping windows and installing Ubuntu, I am committed now 
I think you commented the same on the It’s FOSS article also and I suggested to disable the secure boot. I am glad that worked for you. Enjoy Linux 