Hi
This does sound like a problem with the USB stick.I put it on an old computer running lubuntu and I got the same thing. I'm guessing its a problem with the USB then. Bare in mind I tested it out on an old computer which is also the same make (advent) so that might be why its not working. I really don't know.
It looks like your PCs do not see it as a bootable device so it may not be a problem with the computers but the USB stick itself.
I've just been watching the youtube video.
It shows creating a bootable DVD on Windows. Did you create a bootable DVD and if so, did you use Windows or Linux ?
Kind regards
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