Try as we might, there’s no stopping Windows Vista from gradually replacing our tried, true and beloved XP. Microsoft’s already phasing out XP out on all but the ultra mobile laptop market. So if you’ve already accepted the facts and you happen to be in the market for Windows Vista right now, here’s is a little secret that Microsoft doesn’t want you to know about that will save you $100 on any full version of Vista out there. For those of you who already have an older copy of Windows, be it XP, 2000, 98 or whatever, and were planning to upgrade that operating system to Vista, stop and reconsider after you get all the facts. For those of you who just built spanking new systems and want to install Windows Vista on them, you can save yourself $100.

What Microsoft doesn’t want you to know is that there is absolutely no difference between the full and upgrade editions of Windows Vista, SP1 included. Even though the end-user license agreement states, “To use upgrade software, you must first be licensed for the software that is eligible for the upgrade,” Windows Vista will in fact consider itself as a qualifying product. For those who were already going to buy the upgrade edition, you won’t save any money, but perhaps you may have gained an extra Windows license to use on an extra computer. Certainly a machi ne with older hardware is more suited to run an older operating system. So if I were planning an upgrade, I’d just keep the original XP installation on my machine and wait until the next time I get new hardware to install Vista. This would mean one extra machine in the house that I can use as a backup or bequeath or even sell it to someone. What I’m trying to say is, since you now know that there’s no difference between the upgrade and full Vista editions, why not treat your upgrade edition like a full edition and use it thusly?

The trick to do this is simple and still works even with the new Vista SP1:

1. Boot from the Vista upgrade DVD.
2. Select “Install Now” but do not enter in your product key and disable the option to activate next time you’re online.
3. Do the “Custom (advanced)” install and wait for the install to complete. The process may take a few reboots.
4. After the installation is done, again execute setup from the DVD, but this time make sure you’re doing it from Vista and not your PC startup. You can simply eject and reinsert the Vista DVD.
5. Select “Install Now” and select “Do not get the latest updates for installation.”
6. Now enter your product key and disable the option to activate next time you’re online.
7. Do the “Upgrade” install and wait for the install to complete. Do not boot from the DVD when prompted to do so. Otherwise just sit back and let the install work on its own.
8. After the second installation completes make sure you activate Vista since you didn’t do it during either installation