office xp pro and xp standard

[apalumbo]

I HAVE MANY COPIES OF OFFICE XP AND THEY ARE MIXED UP ,I
DO NOT KNOW WHICH I INSTALLED AND WHICH ONES ARE STILL
GOOD.EACH CD SET ARE WITH THEIR PRODUCT KEY JACKETS.IS
THERE A WAY I CAN TELL WHICH ONES (PRODUCT KEY) ARE USED
(ACTIVATED)AND WHICH ONES I CAN STILL USE(ACTIVATE).IF I
INSTALL OFFICE AND THE PRODUCT KEY HAS BEEN USED ALREADY
IT WILL MAKE ME UNINSTALL FIRST BEFORE I COULD TRY
ANOTHER CD SET. PLEASE HELP