RE: Can I cancel a downgrade from Windows 10 to windows 8?
Since he has a windows 8 key in bios the Windows 8 media is the least hassle to get installed.
Getting installed BEFORE JULY 29 game over is a good idea to get to FREE windows 10 upgrade.
Windows 8 is actually the hardest to install as there is no official Download Link for it. Windows 8.1 with Update 2 and Windows 10 TH2 installation media will also pickup that key.
Tech Enthusiast and Author of the Unofficial Dell Windows Reinstallation Guide