yes, thats what im trying to do, and there is a little program that U can dl that will change the cd-key. the problem is im having some problems with with spyware and adware that microsoft has patches for, but i can't update, however i can't afford to have to start all over on this computer so im trying to fix this without having to reformat and reload it.
Use the new copy to do a refresh (over the top) installation, use the CD-key that comes with it, and all should be well. You'll need to reactivate the installation, but the new CD key should be used for generating the activation code, so it'll go through as a new installation. :)
Be warned, if your system has problems, an over the top install will probably make them worse, not fix them, so you'd need to format and start over anyway if that happened ;)