1. A method for updating configurations of a target system in a computer, the method comprising: booting, based on Preboot Execution Environment technology, a micro-system for updating configurations of a target system before booting the target system, said micro-system performing the steps of: acquiring target configuration packages via a network from a server, the target configuration packages indicating a post-update status of the target system; extracting target configuration data from said target configuration packages; and updating the configurations of said target system by using said target configuration data, wherein said micro-system is independent of said target system.