Multiple, semi-independent virtual operating system (OS) environments coexist within a single (OS) such that a change made in one environment does not affect the main OS or any other environment. In this way each virtual OS environment appears to be an independent OS for the applications running within it. The file system and registry information for each environment is independent of the base OS and other environments. Each of the environments can contain a group of installed applications that will run independently of each other. Although the invention is described in terms of a Windows.RTM. environment, the approach is applicable to other operating systems through appropriate modification.