XPCREATE doesn't require that you edit winnt.sif or cmdlines.txt. You only need to edit these files to ensure they accomplish what you need. My winnt.sif file contains my Admin password, Product Key, etc... The information within the winnt.sif file is what make the CD an unattended CD. It's not required by XPCREATE. My cmdlines.txt only contains the following lines: [Commands] runonce.cmd That's it. I use runonce.cmd to install additional application, such as Acrobat, after XP has been installed. This file is also not required by XPCREATE. It simply allows you to install additional applications, import registry setting, etc.. Both files should be created and edited with notepad. You don't. XPCREATE adds the switches for you. This is why you must put the updates into particular folders.