Talk about Windows 8 downgrading those things

Windows 8 EULA user license agreement shows that consumers who purchase pre-installed Windows 8 Professional PC have the right to downgrade to Windows 7 Professional or Vista Business. Nowadays, Windows 8 has been officially launched. Before upgrading to Windows 8, there must be a lot of users concerned about whether it can be downgraded. Today, we will come back to introduce you to Windows 8 downgrade rights.
Degraded rights are a free service that Microsoft provides to Windows users and are listed in the Windows Software License Terms. Downgrade rights provide a practical solution:
1, purchase a pre-installed Windows 8 Professional PC<2>2, downgrade to Windows 7 Professional or Vista Business Edition
3, when needed Upgrade to Windows 8 Professional, and since it is licensed, the upgrade is free and users can upgrade at any time.
Note that you need a Windows 7 Professional or Windows Vista Business Edition media CD to be downgraded from Windows 8 Professional.
Understanding downgrade rights:
http://www.microsoft.com/oem/zh-hans/licensing/sblicensing/Pages/downgrade_rights.aspx?mtag=HP-P-W8#fbid=1sNUdGPTWF3
Downgrade rights details and frequently asked questions:
http://www.microsoft.com/oem/zh-hans/licensing/sblicensing/Pages/what_to_do_downgrade_rights.aspx#fbid=1sNUdGPTWF3