Help! Windows 10 Error

[Coriander]

So I recently built my second pc, and threw my ssd into it. Now windows is saying that I need to activate it, even though I had already done that while the ssd was in my previous pc. What caused this and how can I fix it? I don't have the product key on me anymore.

[jiyeon]

It's because it's a new motherboard. If you change motherboards, Windows won't be able to recognise the BIOS and therefor you need to reactivate.