VLK license without reinstalling XP Pro

Sir,

good day, im a new lan admin guy and my boss told me to install all original windows xp pro on the computers 31 PC’s, eventho’ it is registered (still with coa stickers) …

all the pc’s are working great but he insist on reinstalling the VLK keys…

the question is how can i do this without reinstalling windows? 🙁

do i need to use a key changer or something.. sorry, im new here 🙂

regards! 😛