A system, method and computer program for launching an application into a host OS, include storing a snapshot/image of a Virtual Execution Environment (VEE) on a portable device, wherein the VEE snapshot is packed into a self-extracting file; launching the VEE from the portable device on a computer connected to the portable device; and starting a user application within the VEE. The VEE snapshot can be restricted in one of its total usage time or absolute time. The VEE can be, e.g., a Virtual Private Server or a Virtual Machine. The user application is a non-native application for a host OS of the computer. The VEE is launched from an icon on the portable device. The portable device can be, e.g., an iPod, a flash memory card, a digital player, a mobile phone device, a portable gaming device, rewritable CD/DVD/HD DVD/Blu Ray disk and write-once CD/DVD/HD DVD/Blue Ray disk. Alternatively, some of the data (such as user-specific data) can be stored on the portable device, while other data (such as OS executables, DLLs, etc.) can be downloaded from a network.