WINXP PRO Activation Key

I customer that purchased 200 HP PCs that were preloaded with WXP Pro. This customer chose to discard WINXP Pro and reimage all of their PCs with WIN2K Pro.

They threw away all of the WINXPPro Installation CDs and I picked up oe of them. I would like to know if the license for the Activation is good. Can I install WIN Pro on another PC and Activate it through Microsoft procedures?