I purchased the upgrade version of Vista Business and would appreciate
verification of what I've found:
When doing the upgrade, it required a pre-existing installation of a valid
O/S, like WinXP SP2. It is not sufficient to input just a license key
from
the older valid O/S, so if you ever need to re-install Vista, you have to
reinstall the older O/S first. Ouch.
Is that right or did I miss something?
Yes the upgrade process is different in Vista. It does not do a shiny media
check as in XP (you didn't have to input a product key, I'm not sure what
you are thinking of. In XP when doing the upgrade you would insert the CD
for the qualifying OS early in the install process when prompted as proof of
ownership).
To install from a Vista upgrade DVD, it's designed to start the installation
from the desktop of the installed, qualifying OS. That said there is a way
to install an upgrade version of Vista on a bare hard drive. You still have
to own a qualifying OS. This process doesn't remove that requirement.
It involves doing two installs, the first one you install the version you
have a product key for on the bare drive, but don't enter the product key.
Then you run an upgrade on that with the same DVD, and in that second
install you enter the product key. Here is an article on how to do it.
http://www.dailytech.com/article.aspx?newsid=5932
To avoid the hassle of reinstalling the qualifying OS or doing a double
install, if something damages the Vista installation that you can't repair,
image the system using something like Acronis True Image Home version 10
saving the image on an external hard drive.