well actually even microsoft allows u to change ur cd key ( there is a microsoft way )
so as long as he hasnt mentioned hes using a pirated version ... this is pretty much legal i think
there IS a software which lets u do this ...
but im not sure whether the software is legal ...
so basically in the end ... ur stuck with no help
why dont u go meet google ... have a few drinks ... become good buddies ... and maybe google will help u out ?