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Prayaya enables you to create a virtual operating system on your hard disk or any removable storage devices. If you install it on your hard disk, you will be able to install and run your software, manage your stuff, such as files, folders, bookmarks, desktop settings on a virtualized environment independent of the host computer; If you install it on a removable device, you will be able to carry your own personal system and software with you on a USB flash drive, removable hard disk or iPod device so that you can have access to your own stuff, including your applications, files at any time and anywhere as long as you connect your removable devices with a PC.
Freeware
http://en.prayaya.com/index.html