Vista upgrade DVD can be clean installed
Microsoft internal documentation reveals workaround for Vista Upgrade DVDs with no need for a previous version of Windows, This workaround allows users to perform a ?clean install.? The process is a bit tedious, but is not hard at all to complete. Check out the source here.
Essentially you can now buy?the retail ‘upgrade’ version of Vista and?get?the ‘full version’ with a few simple steps, whoopee!