That double install method... ugh. :D
I had a post long ago under another nick where I showed people how to do a more simple 1 install 3 commands from an Admin Command Prompt method after the installation was done method but that thread got lost (also long ago) during a forum rollback because of some problems. That's still my recommended method and I used it over 1500 times over the course of a year of installing Vista for people without one issue or failure.
Of course, other people said it didn't work for them so I had to wonder what they were doing wrong, but never figured it out. Anyways, there is a simpler way to do it:
1) Install the edition of Vista you purchased without putting in the key and choosing it manually from the list of OSes available as those other guides instruct.
2) When the installation is done and you're actually running Vista, take care of all your Windows Updates, your driver updates, your software installations, etc. Set the machine up the way you want and then verify everything is working and solid and isn't giving you shitfits for some problems, crashes, etc. When it's working just as you want, move on to...
3) Click the Start Button, find the Command Prompt shortcut on the Accessories list. Right click on the shortcut, choose Run as Administrator. When the window appears, verify it says Administrative Command Prompt at the top or this won't work.
4) Type the following commands in sequence and insert your Product Key as noted with the hyphens but just the key itself not the <>):
slmgr -ipk <Product Key> and then press Enter
It takes a minute or two on most machines for this process to complete. When it does a dialogue box will appear to tell you that you have installed a product key using the manual process by command line.
slmgr -ato and then press Enter
This also takes a minute or two on most machines for it to finish. When it does a dialogue box will appear to tell you that you have activated online successfully.
Technically that's it, but to verify things are OK across the board, there's one final command:
slmgr -dlv and then press Enter
Same thing, takes a minute or two to finish, then a dialogue appears because you've done a license verification. The box gives info about the type of license you have, effective date, etc.
Simple, quick, efficient, and a one-shot method proposed by me way back in November of 2006 and used countless times by many people to get past that waste of time dual installation method which still becomes an in-place upgrade more than anything else.
BLEH for dreaded inefficiency!!!
In the end, when its all said and done, does this way have the exact same outcome as the double install/upgrade?
I mean will one be better than the other (not in terms of process, but in terms of finished result)