
Hey Gigi,
You need to reinstall the OS, whenever you rebuild a PC this way, it is important to reinstall. I would take the time to repartion and reformat as well. If he has files that he needs, you will do better to reinstall the HD and the CD on his old PC, then backup his files onto a CD.
Reinstall the HD and CD back to the new system, and repartition,reformat and reinstall the OS.
Let us know how it goes,
TTFN
LGW