However, you can still get Windows 10 for free after this by entering a Windows 7, 8, or 8.1
key during the installation process.
Don't provide
any key during the installation process.
If you didn't enter
a key during the installation process, you can enter a Windows 7, 8, or 8.1 key right in this window when you're asked to provide a Windows 10 key.
Even if you don't provide
a key during the installation process, you can head to Settings > Update & Security > Activation and enter a Windows 7 or 8.1 key here instead of a Windows 10 key.
Not exact matches
Twice
during the
installation process, I was prompted to enter a product
key.