Explanation/Reference:
Explanation:
You should keep the following in mind prior to and during the upgrade from Windows Vista to Windows 7:
Perform a full backup of the computer running Windows Vista prior to performing the installation.

That way, if things go wrong, you can do a full restore back to Windows Vista. You must ensure that

Windows Vista has Service Pack 1 or later installed before you can upgrade it to Windows 7.
Ensure that you have the Windows 7product key prior to the upgrade.

You cannot upgrade between processor architectures. A x86 version of Windows Vista cannot be

upgraded to a x64 version of Windows 7, and vice versa.
You can upgrade only to an equivalent or higher edition of Windows 7.

You can upgrade Windows Vista Home Premium to Windows 7 Home Premium, Professional,

Enterprise, or Ultimate, but not to Windows 7 Starter. Windows 7 Professional is equivalent to Windows Vista Business.
Ensure that there is at least 10 GB of free disk space on the Windows Vista volume prior to attempting

the upgrade.
Windows 7 Home Premium, Professional, Ultimate, and Enterprise editions have the following minimum hardware requirements:
1 GHz 32-bit (x86) or 64-bit (x64) processor

1 GB of system memory

A 40-GB hard disk drive (traditional or SSD) with at least 15 GB of available space

A graphics adapter that supports DirectX 9 graphics, has a Windows Display Driver Model (WDDM)

driver, Pixel Shader 2.0 hardware, and 32 bits per pixel and a minimum of 128 MB graphics memory