Well you could try this idea. Get a valid copy that's been registered or activated. Then install it, and call the number (if there is one in vista) for validation. When they say that it can't be validated, they'll redirect you to an indian support person. You tell him that a virus got ahold of your computer and crashed it, and you're reinstalling windows. He'll then give you the validation key.
That's what I do with windows XP, I don't know if it's the same with vista, but hey, it's worth a shot.
Corey