orion2, many people on this forum say the answer is Disk.Config, it doesn't work for me though. I have Windows XP SP2, and Disk.Config is not documented anywhere in ref.chm or deploy.chm. furthermore, I put the following winnt.sif into an iso image and test it on a test machine, I want to make C: 3 GB, other drives I will quick format them using batch scripts (but the result of this winnt.sif is a C: partition taking full space): Please help. edit: you specified [DiskConfig], I think you meant [Disk.Config] ? anyway both of them doesn't work for me.