i'll try to explain it but not detailed: you got to stablish a first variable in this case, %CDROM% so first portion of code it's for the 1CD, next we stablish a second variable, last portion of code, which is %OFFICE%. both codes go to your runonceex. to do this we need in the first cd CD1.TXT (that contains the main installation of xp) and in the second cd we put CD2.TXT (this is our new created cd that contains office). for a deeply explanation refer to first post.