I recently purchased a second hand PC, that it came with Windows 7 preinstalled. I have already upgrade the OS in my laptop from Windows 8 to Windows 10 and I am quite used to Windows 10 features, especially the mouse scroll feature that doesn’t require the windows to be on focus. This feature is not available in Windows 7 which really bother me dealing with multi windows.
Microsoft did offer Windows 10 free upgrade for Windows 7 and Windows 8/8.1 user but I missed that window that ended on 29th July 2016. Searching for alternative way for Windows 10 free upgrade, it brought me to a few page saying that the free upgrade is still possible now (end Dec 2016) by accessing this page (link)