Change CD Key

I have several old computers from a recycling team i am part of. we rebuild the computers and donate them. we have a bunch of computers that have all the same parts so we wanna use ghost to clone one and deploy the copies to all the others to make it easier for us but one question we are using the cd keys on the cases their windows 98 keys and they work with the disks we have but since we wanna clone it all the computer would have the same key. how can i change the key in each computer without actually installing windows 98 individually on each system

Thanks In advance,
Nick