Reuse a product key?

[JokeR_14]

I built a pc and bought a product key to activate windows using the usb tool and now I'm having some problems with my pc so I want to start new reusing the usb tool. My question is ; Can I reuse the same product key ?

 

[Colif]

You don't need to know the key anymore. When you installed win 10 on the PC the first time, it was recorded on a Microsoft server alongside the details of your PC

When you reinstall it and get to screen asking for a licence, click the link that says "I don't have a key" and win 10 should auto activate once its installed.