What are the basic facts of the Windows 10 upgrade?
Microsoft is making Windows 10 available as free upgrade for qualified Windows 7, Windows 8.1, and Windows Phone 8.1 devices. It will be available starting July 29, 2015; people can reserve their free upgrade today.
You only have until July 29, 2016 to take advantage of this offer. Once you upgrade, you have Windows 10 for free on that device.
Is the upgrade really free?
Yes, it’s free. This is a full version of Windows, not a trial or introductory version. It is available for a limited time: you have one year from the time Windows 10 is available to take advantage of this offer.