Many machines do not have drivers for the machine and then Microsoft doesn't support older windows on new CPUs.
If it's just the menu system, replace it with Classic Shell and be done with it.
As to the last question. No.
I have a computer running windows 10, but my sister prefers windows 7. She likes the look and isn't a fan of the new windows 10 look. However I like windows 10 so I want to keep it. So is there a way I could duel boot windows 7 and still have all the files in that OS. She has a lot of files and games and stuff and I don't feel like reinstalling them. So can I install windows 7 and still have all the programs and stuff?
Thanks in advance!

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