Where is the upgrade matrix?  What SKUs of Vista will upgrade to what SKUs of W7?

 

Windows Vista™ Enterprise cannot be upgraded to Windows 7 Ultimate. You can choose to install a new copy of Windows 7 Ultimate instead, but this is different from an upgrade, and does not keep your files, settings, and programs. You’ll need to reinstall any programs using the original installation discs or files. To save your files before installing Windows, back them up to an external location such as a CD, DVD, or external hard drive. To install a new copy of Windows 7 Ultimate, click the Back button in the upper left-hand corner, and select “Custom (advanced)”.