Computer tools and methods novelly combine periodic backup and restore features with migration features to transfer the components of a failed system to a new system, which new system may be dissimilar to the old system. As well as backing up and transferring critical data files during the disaster recovery operation, the present invention also transfers, inter alia, applications, user states, hardware settings, software settings, user preferences and other user settings, menus, and directories. In another aspect of the present invention, a network of shared end-user computers periodically backs up each individual end-user computer to a central instrumentality, in a novel manner to reduce storage and time requirements. That is, redundancies for the end-user computer backup files are eliminated or greatly reduced by only making reference to but not storing components that are generic to the system, and further for each previously stored component, only storing differential or incremental information, unless predefined conditions are met. In yet another aspect of the present invention, remote end-users upload, via a wide area network such as the Internet, backup information to a central location. In the case of end-user computer failure, backup and migration information can be delivered to a new machine by means such as mailing a storage medium (e.g., compact disc), and downloading from the Internet.