You can get Windows 7 if you purchase refurbished (actually great deals and every machine in my home and office is a refurbished unit and been very reliable.
On Windows 10, I went with it for my personal machine only because Windows 7 support runs out in 18 months (or less). I had XP before and was tired of the constant non-longer supported issues). Windows 7 is great and more familiar. I gotta say, though, except for a few things I don't like, Windows 10 is working for me.
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Where can you buy refurbished machines with Win 7?
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