A Virtual Machine (VM) is a software program or operating system that not only exhibits the behavior of a separate computer, but is also capable of performing tasks such as running applications and programs like a separate computer. A virtual machine, usually known as a guest is created within another computing environment referred as a "host." Multiple virtual machines can that allows a vitrual Operating System to run on top of whatever OS is controlling the hardware. One major benefit of a VM is if it crashes, it can be quickly and easily started from a saved safe state. Multiple virtual machines can also exist within a single host at one time. A virtual machine is also known as a guest. -techopedia, and can be run cheaply from the cloud by services like Amazon's AWS.