You have less that 10 days to register your systems hardware with a Microsoft Activation Server and make your system a Windows 10 Device if you haven’t already done so…
After this date you “may need to pay full retail price” to Upgrade to Windows 10 when Windows 7 and Windows 8.1 approach End of Life (2020).
Its advised to Backup your Windows 7 or 8.1 Installation using Macrium Reflect so you can easily revert if need be. Before upgrading you should Update your (UEFI) BIOS. You then can then Upgrade to Windows 10 TH2. After the Upgrade you may Restore your old Windows Installation using your Macrium Reflect Image.
Alternatively you may backup your files and Clean Install (recommended particularly if you plan to migrate). See Download Windows 10 TH2 and Clean Install.
I have bought several second hand Windows 7 OptiPlex 390/790/7010 models this week that aren’t yet upgraded to Windows 10. I plan on using these to see if the Free Upgrade will continue to work after the 1 Year Free Upgrade period. I will report my findings…