i had a couple used laptops lying around so i decided to make them a spare time repair project. the hard drive on both had to be replaced due to the bios not recognizing them on booting up but instead of buying new ones i used salvaged ones. mind you i didn't reformat them upon installation simply because i wouldn't have to buy a windows media disc. both of the hard drives have the pre-installed versions of windows already on them. now im trying to upgrade windows but the product keys wont work because they aren't in their original system. the product keys are valid.is there any way to use those keys to aid me in my upgrade or will i have to break down and reformat and purchase a windows media cd.