I love Microsoft. We had just started to resign ourselves to the fact that we were going to need Windows XP on our hard drive if we ever had to reinstall our upgrade version of Vista. Then they
came up with a solution
left open a gaping loophole. That's right, you can install the upgrade version of Vista on a blank hard drive. The bad news? The workaround's almost as much of a pain in the ass as the original problem, requiring multiple installs...
Basically, start the setup for your upgrade version of Vista on a blank hard drive, but don't enter the product key. Instead, install it as a 30-day trial. Once Vista's up and running, run setup again, entering your product key this time. Do a clean install, then pat yourself on the back for
not having to keep XP around in case you want a new hard drive at some point.
Act fast, cause there's no telling how long this little hole's going to stay open.