oem license

I got a new laptop and swapped the only SSD with a different completely wiped SSD from my old laptop (used shred on linux from USB). This meant that when I turned it on again, I needed to reinstall Windows, which I did. I intended to not use a key to activate right away and install the Windows...

Folks, I need the best step by step for updating hardware. I just bought an older Dell PC with a Windows 10 license (assuming OEM Windows 10 Home)--I also assume it will be pre-installed on the cheap hard drive. This is an ebay refurb unit. I only wanted it for the case and Windows license...