Abstract: Software is updated easily and efficiently and in the same time, thereby reducing the load imposed on the user side, the software vendor side and the center computer side. When the user computer sends user ID to the center computer, the center computer have the user computer obtain URL of the module-storing region that corresponds to the user ID and stores the modules that the user should obtain. The user computer accesses to the module storing portion using the URL, obtains a list of modules, compares the list to the modules that are currently installed in itself and judges whether it is necessary to obtain modules. When judged that modules are needed to be obtained, the user computer accesses to the module-storing region again and obtains the module.

Abstract: To update software easily and efficiently and in the same time reducing the load imposed on the user side, the software vendor side and the center computer side. [Means for Solving] When the user computer 103 sends user ID to the center computer 102, the center computer 102 have the user computer 103 obtain URL of the module storing region 104 that corresponds to the user ID and stores the modules that the user should obtain. The user computer 103 accesses to the module storing portion using the URL, obtains a list of modules, compares the list to the modules that are currently installed in itself and judges whether it is necessary to obtain modules. When judged that modules are needed to be obtained, the user computer 103 accesses to the module storing region again and obtains the module.