Method and system for configuration of virtualized software applications

A method of virtualizing an application to execute on a plurality of operating systems without installation. The method includes creating an input configuration file for each operating system. The templates each include a collection of configurations that were made by the application during installation on a computing device executing the operating system. The templates are combined into a single application template having a layer including the collection of configurations for each operating system. The collection of configurations includes files and registry entries. The collections also identifies and configures environmental variables, systems, and the like. Files in the collection of configurations and references to those files may be replaced with references to files stored on installation media. The application template is used to build an executable of the virtualized application. The application template may be incorporated into a manifest listing other application templates and made available to users from a website.