Subscription/renewal query

Hello all

I have 3 pc's running Win XP pro, all with a current subscription for Nis 2010 with 45 days left, now the complicated bit !!

 

In one PC, I have fitted an extra Hard Drive (multi Boot) with Windows 7 Home Premium installed.

I have purchased a new (boxed) 3 user version of Nis 2010.

If I install this first on PC1 Windows 7 HD, will I be able to just add the product key to HD 2 Windows XP pro & also to PC2 (using up the 3 user limit).

I assume that this will leave PC3 with 45 days subscription remaining,.......... am I correct with this assumption?

 

Regards