Thanks for the info Gosh. Since I don't have access to WinPE I'm afraid I will have to find a method in DOS to: - get the size of the hard disk - based on that size determine what needs to be allocated to partition 1 and partition 2. For example partition 1 can be max 8Gb but shouldn't take more then 50% of the entire hard disk. I looked at several possibilities. But all of them (fdisk, gdisk, delpart, ...) didn't give me an easy way of doing that. Does anyone know about a Dos-based scriptable tool or method that would allow that ?