way to 'downgrade' with a valid key?

OK, I bought ultimate, and picked up the 1/2 off for (2) Home editions.

Through new motherboarding and inattentive re-installing, I now have (2)
Ultimate editions and one is 'invalid' and stopped working. I need to
downgrade one of them to Home edition (for which I have a valid number)

Is there a way, other than re-installing, to downgrade from Ultimate to
Home Edition ?

Both machines now have enough 'stuff' to make reinstalling a pain.

Help, Please.

A 'downgrade' requires a clean install.

--
Jane, not plain 64 bit enabled :-)
Batteries not included. Braincell on vacation ;-)
"JDoe" <> wrote in message
news:W2rKh.33653$...
> OK, I bought ultimate, and picked up the 1/2 off for (2) Home editions.
>
> Through new motherboarding and inattentive re-installing, I now have (2)
> Ultimate editions and one is 'invalid' and stopped working. I need to
> downgrade one of them to Home edition (for which I have a valid number)
>
> Is there a way, other than re-installing, to downgrade from Ultimate to
> Home Edition ?
>
> Both machines now have enough 'stuff' to make reinstalling a pain.
>
> Help, Please.
>