My question has to do with my windows product key....

A few days ago I wipe my harddrive clean of Windows XP, so i went out to the
store and brought a new copy of windows XP Home OEM full version. So i
install windows xp with the new product key. My question is since that i wipe
my harddrive clean of windows xp, can i used my old product key, for a
computer that i am going to build?