1. A method for accessing, by application programs, resources provided by an operating system, the method comprising the steps of: (a) receiving, by a process executing outside an application isolation environment, a request for a resource and an identifier associated with the resource; (b) determining that the requested resource resides inside the application isolation environment; (c) redirecting the request for the resource and the identifier associated with the resource to the application isolation environment; and (d) responding to the request for the resource using an instance of the resource residing inside the application isolation environment.