Aqui é onde as respostas geralmente vêm: link
1: Pela primeira vez, a ativação funcionará da mesma forma que qualquer ativação pela primeira vez. A ativação on-line deve funcionar, mas, se não, a chave única será exibida a você para fornecer ao sistema ou operador automatizado do telefone. Se ativado mais de uma vez, é mais provável que você use o sistema de telefonia.
Q. Will the downgraded software require product activation? If so, what product key should be used to activate the software?
A. Once the downgraded software is installed, the PC will prompt for a product key in order to activate the software. The product key associated with the original Windows software should be used for activation. If the product key has been previously activated, which is likely if the media came from a prior legally licensed version that has been activated in the past, the software may be unable to activate over the Internet, due to the hardware configuration change when installing this media onto the Windows 8 or Windows 7 system. When this happens, the appropriate local Activation Support phone number will be displayed, and the person performing the downgrade will need to call the Activation Support Line and explain the circumstances to a customer service representative.
2: sim. Isso pode ser feito com qualquer mídia legal, exceto OEM. A mídia OEM está vinculada à estação de trabalho específica, pois a licença está "vinculada" à placa-mãe da estação de trabalho
Q. Can a PC with an OEM Windows operating system have its motherboard upgraded and keep >the same license? What if it was replaced because it was defective?**
A. Generally, an end user can upgrade or replace all of the hardware components on a computer—except the motherboard—and still retain the license for the original Microsoft OEM operating system software. If the motherboard is upgraded or replaced for reasons other than a defect, then a new computer has been created. Microsoft OEM operating system software cannot be transferred to the new computer, and the license of new operating system software is required. If the motherboard is replaced because it is defective, you do not need to acquire a new operating system license for the PC as long as the replacement motherboard is the same make/model or the same manufacturer's replacement/equivalent, as defined by the manufacturer's warranty.
The reason for this licensing rule primarily relates to the End User Software License Terms and the support of the software covered by those terms. The End User Software License Terms are a set of usage rights granted to the end user by the PC manufacturer, and relate only to rights for that software as installed on that particular PC. The system builder is required to support the software on the original PC. Understanding that end users, over time, upgrade their PCs with different components, Microsoft needed to have one base component "left standing" that would still define the original PC. Since the motherboard contains the CPU and is the "heart and soul" of the PC, when the motherboard is replaced (for reasons other than defect) a new PC is essentially created. The original system builder did not manufacture this new PC, and therefore cannot be expected to support it.
3: Não. O MS não emitirá uma nova chave porque não há necessidade. A chave de ativação pode ser diferente, mas a chave real do produto é usada para o downgrade.