How can I know if license would be valid for re-install on same lapto?

I got the Windows professional OS pre-installed i.e along with my laptop. In the same way my brother got Windows Ultimate. My brother's is planning to do a clean install. Can he use the same key that is on the sticker of the installation disk that came along with the laptop or purchase a new one? I mean does it become invalid if he formats and re-installs on the same laptop? If yes how can he avoid re-installation?

   Information

We always assume you have made your Recovery Disks using the OEM manufacturer's Recovery Media Creator app the first day you had your new PC.
& made the Startup Repair CD.
startup repair disc-create

Did you make the OEM manufacturer's Recovery Disks?
If yes, need to use the key.

No, we don't have any recovery disk

I would make the Recovery disks.

theog said:

I would make the Recovery disks.

Sorry, I didn't understand what's the connection between Recovery disks and clean re-install.

bigmck said:

As long as your brother clean installs Ultimate, he can use the key on the sticker. Same with yours, you must install Professional and you are allowed to use the sticker key. There is no limit on the number of times you can reinstall as long as you do not change the motherboard. == Theog was suggesting you make the recovery disks, as he put in his post #2 above, before you clean install. It is more than a suggestion. It is a MUST.

Thanks Bigcmk, I'll look in to that recovery disk thing. I didn't make one till date, I'll try one.

AddRAM said:

Are you saying your brother`s laptop came with windows Ultimate installed ? ( That`s a little unusual ) you better make sure that`s what his COA says.

And yes, he should be able to use the key that came with the installation media again.

Yeah, I don't know why you are saying it's unusual. Here at my place we have the choice of selection of OS when we purchase. Recently one of my friends got a laptop with Linux (maybe Red Hat, IDK for sure) and it costed him some 4500 INR i.e 75 USD less than a Windows OS version of same laptop. My brother got a DVD with that Windows key.