There are many Virtual Operating System similar to your system OS. You can buy for small amount. But SilveOS.com provides a free Virtual Operating system Environment.
SilveOS.com is a Microsoft Silverlight based online virtual operating system, it simulates OS inside a web browser. SilveOS.com replicates the desktop environment of a Latest operating system like Windows 7. you can launch applications with out Installing them. Cool isn’t it?
Full Img: Click Me
SilveOS.com is web-based and requires Silverlight 2 to operate. currently it includes taskbar, start menu and sidebar and applications like
* File Explorer
* Internet Explorer
* Video Player
* Virtual Earth
* Rich text editor
* RSS reader
* YouTube Viewer
* Games like Chess, Solitaire, etc