FYI for anyone still stuck on Windows 10. There is a useful feature in Windows 10 instal media. It allows people with a valid Windows 7 product key to still do the free upgrade via fresh instal of Windows 10.
During the instal it will accept a Windows 7 product key and authenticate your instal and register it with Microsoft.
Of course the usual warnings about making a backup first apply. Perhaps a good time to invest in a new SSD disk drive.
One of my Sony VAIO laptops upgraded fine but then after an update gave a black screen. Took a lot of fiddling to fix it and involved stopping the NVIDIA display driver installing.
Adrian