As everyone else has said you need the correct cd to go with your cd-key. But i dont think you have grasped the fact there is three sub-versions the two main versions of XP, Home and Pro. The three subversions are Retail, OEM and Volume(corp). These three subversions require seperate keys alone. Eg You could have a copy of Home and a Home Cd-key, the cd is a retail cd, and the key is an VOL key, that kind of combonation will not work. This is what i think Allanol and Tsunami was trying to tell you. EDIT: This may be of some help but bare in mind it, altering the setupp.ini violates the EULA