How to create a virtual machine in windows

Virtual Machine , It is a software program designed to run as an application without actually interacting with existing operating system. Virtual Machine is created using a software program that itself specifies amount and what hardware resources are permitted to use by the virtual machine. Virtual Machine creates an environment where processes in that environment can be executed without interacting the actual operating system and hard disk. Virtual Machines are differentiated by the degree of resemblance it has to a Real System and are categorized as System Virtual Machine or Process(Application) Virtual Machine.
A Virtual Machine can be an application running inside an operating system as a single process or it can be different Operating Systems running in parallel on a Real Machine. There is lot more to understand by the term Virtual and it means lot more in technology but as a whole what you can think of a Virtual Machine is

Secure and no chance of your operating system being effected with virus executed inside virtual machine
a Software Program where amount of resources can be programmed as per requirement in software

Most common usage scenario of a virtual machine is running multiple operating systems at a given point of time on a single machine , If you wonder how could this be possible then you have to try installing virtual box on your computer. Using Virtual Box you can have multiple operating systems running at a single point of time , For instance if you have windows operating system on your machine you can install linux operating system as an application inside your windows operating system and following is the procedure of how to install linux in virtual box

How to install linux (ubuntu) in a virtual box

Virtual box is a software program to create a virtual machine on your desktop, There are many such software programs and here is the setup procedure for virtual box. Follow the steps in orderly manner to install ubuntu in your virtual box.