If you have DVD media or and ISO of your Operating System, you can quickly and easily create a sysprepped VHD or VHDX image. With this Virtual Hard Disk file, you can set up a Virtual Machine and boot it directly to the Out of Box Experience, thus saving about half an hour to an hour of installation time.

The process for doing this and PowerShell script called Convert-WindowsImage.ps1 is documented in the Technet Script Repository here – http://gallery.technet.microsoft.com/scriptcenter/Convert-WindowsImageps1-0fe23a8f

Note: This latest release (v6.3) now supports the creation on Generation 2 VMs.