I do have a DVD. I was thinking of it, but the .iso worked w/o burning. So, I won't need it - but still I want a USB stick to work. That is my preferred media.
Thanks for your explanation. And I thank Saltgrass too for his. I still say it's fishy for the error message to say "this PC can't be upgraded to Windows 10" & "hardware that isn't ready" when I have upgraded & the hardware works just fine
Maybe it should have said, "your hardware is fine, but we can't handle more than one drive letter". But that doesn't really make sense, either, since some sticks do work.