Using windows 7 product key from old laptop

[EfoDom]

I've recently built a pc - windows 10 but not activated. I have an old laptop that I don't use anymore. Could I just use the product key from there to activate windows 10? The product key is on a sticker on the back side of the laptop. Or would I have to remove windows 7 from that old laptop first?

 

[Dark Lord of Tech]

The license key on the Laptop is tied to that Laptop's motherboard , time to purchase a new license.