I have successfully cloned my 80gb hd to 250gb using Acronis 9.0 full store bought program. But when I take out the 80gb and install the 250gb as master when I boot up I get the message "Operating System Missing". I understood that cloning copied everything. Am I wrong? Does this have anything to do with the MBR that I have read about in other posts? What is an MBR? If this helps, my system does recognize the 250gb as master. Is Imaging a better solution? I am cloning the original hd of a Sony Vaio PCV-RZ 32G if it makes any difference?