Questions about activating Windows

[jjcz5]

If I install Windows 10 for free then activate it down the road ether using a Key or a digital license would I have to uninstall and reinstall anything like OS itself or any drivers?

Buying Windows 10 it comes in a box with a USB inside but since I would already have Windows installed on my PC what do I do with the USB?

[Needfuldoer]

It should take the license as long as it's for the same edition of Windows you installed. (Home license for Home, Pro license for Pro, etc.)

 

7 minutes ago, jjcz5 said:

Buying Windows 10 it comes in a box with a USB inside but since I would already have Windows installed on my PC what do I do with the USB?

That's just a copy of the install media you can download for free from Microsoft. You shouldn't have to use it.