Nice reminder Narendra, I have one pc on Windows 7 Home Retail that I didn't do the free upgrade on. I'll tick the box for 'using Ease of Access' and get the free upgrade from Microsoft. Thanks.
Narendra's link is to the PCAdvisor article explaining 'Still running Windows 7 or 8? Here's how to install Windows 10 and still get it for free even though the upgrade deadline is long gone.'