I think so far everyone is enjoying 10! I'm happy to hear this. No one liked the new layout of 8 when it came out, and a lot of people had problems with Vista.
Phill Here's the "official answer from Microsoft":
"Can I get Windows 10 if I have a device running Windows XP or Windows Vista?
You may purchase Windows 10 from the Microsoft Store or other retailers and install it on your existing device running Windows XP or Windows Vista if your device meets the minimum spec requirements for Windows 10. You will need to back up any existing files before installing Windows 10. It will be a “clean” install.
However, we recommend you experience Windows 10 on a newer device. We think you’ll be happier with the affordable, great PCs that are available today. PCs have improved dramatically since Windows XP was released in 2001 and Windows Vista was released in 2006. "
Found here: http://www.microsoft.com/en-us/windows/Windows-10-faq
Free upgrade minimum system requirements are here: http://www.microsoft.com/en-us/windows/Windows-10-specifications#sysreqs
Sorry, it looks like you'd have to pay to upgrade the machine running Vista IF it meets minimum specs.
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