Can I use the same Windows 8.1 key to reinstall Windows on the same PC?

[vaconcamp]

A couple months ago I got a key from onthehub.com for Windows 8.1, but now I need to reformat and I was wondering if I would have to call Microsoft to deactivate the key that I'm using now so I can reinstall using that same key on the same PC. Is this true? Does it only matter if it is on different hardware?

 

[USAFRet]

You can use that same key to reinstall.

 

[vaconcamp]

You can use that same key to reinstall.

Do you have any idea how Windows knows it's the same PC? For example, if I replaced my motherboard would that key still be bound to this PC or would it detect it as a different one?

 

[USAFRet]

You can use that same key to reinstall.

Do you have any idea how Windows knows it's the same PC? For example, if I replaced my motherboard would that key still be bound to this PC or would it detect it as a different one?

With Win 8/8.1, you can even change the motherboard.

How does it know? When you activate it and it phones home.

It may activate fine, or it may inform you "This key is already used", and then give you a phone number to activate via the phone robot. Easy and painless.
Sometimes that even happens when reinstalling on the same hardware.