EDITAR : Visite o site Windows.com. A página Comprar o Windows Landing tem uma oferta para atualizar qualquer PC com Windows (XP e superior) para o Windows 8 Pro por 24,99 libras.
Por favor, ignore o resto do post
De acordo com o site fornecido por AbhishekGirish , a oferta de atualização do Windows está disponível apenas para usuários com licença válida do Windows 7 (também em novos computadores com Windows 7). Como você tinha a licença do Windows Vista, isso não é aplicável para você.
Eligibility Details
The offer is for customers (e.g. home users, students, and
enthusiasts) who purchase a qualified PC. A qualified PC is a new PC
purchased during the promotional period with a valid Windows 7 OEM
Certificate of Authenticity and product key for, and pre-installed
with:
Windows 7 Home Basic;
Windows 7 Home Premium;
Windows 7 Professional; or
Windows 7 Ultimate.
The promotional price is limited to one upgrade offer per qualified PC
purchased, and a maximum limit of five upgrade offers per customer.
Key Dates
You must purchase a qualified Windows 7 PC between June 2, 2012 and
January 31, 2013 to be eligible for this offer. The last day to
register and order your Windows 8 upgrade is February 28, 2013.
No entanto, há uma reviravolta no final, dizendo que uma vez que você tenha a chave, ela é válida para a atualização de qualquer PC com uma licença válida para Windows XP, Vista ou Windows 7.
Upgrade Software
Each upgrade license will apply to only one PC and may only be
installed on PCs with a valid base license to a qualifying operating
system (i.e., Windows XP SP3, Windows Vista or Windows 7)
A FAQ responde à maioria das perguntas que você fez:
If I purchased a qualifying PC with Windows 7 Professional on it during the promotion period, but downgraded to Windows XP SP3, does the PC still qualify for the Windows Upgrade Offer?
Yes. The Windows
version on the Certificate of Authenticity and related product key are
what is relevant for eligibility, not the version of Windows being
used. Note that the upgrade experience may vary based on which version
of Windows is installed on the PC.
What edition of Windows 8 will I receive when I upgrade?
A download of Windows 8 Pro (Upgrade)
Do I have to install the Windows 8 upgrade on the eligible PC, or can I install it on another PC?
The upgrade offer is tied to a
Windows 7 PC purchased from June 2nd, 2012 through January 31, 2013,
but you can choose to redeem the offer and install the upgrade on any
compatible Windows-based PC with a qualifying base operating system.
Finalmente, a questão principal. Você precisará ATUALIZAR uma instalação do Windows conforme o contrato de licença para a oferta de atualização.
Does the upgrade need to be done on a PC with Windows already installed?
The license terms for the upgrade require upgrading from
a valid "genuine" version of Windows. Visit
http://www.microsoft.com/genuine/ if you are not certain whether or
not your PC has genuine Windows.