If people were already happy with the news that the upgrade to Windows 10 will be free for the first year, they'll be even happier now. Microsoft's Gabriel Aul has confirmed via Twitter that you'll be able to do a clean reinstall of Windows 10 on machines that have been upgraded for free—even if you've completely wiped the drive. As a bonus, you won't need your old Windows product key to do it, as the device in question should activate just fine with Windows 10.
Most of us have probably had to reinstall Windows a few times over the years due to accumulated crud, and nuking from orbit is sometimes the only way to fix others' malware-ridden PCs. Given those situations, the confirmation that a clean install of Windows 10 is possible on upgraded PCs is welcome news indeed.