You want to install another version of Windows on existing system ?
- create vdisk via computer manager (size min 16GB type fixed)
- create bootable usb key with setup
- boot on usb key
- follow setup instruction
- on the screen with choice update / custom : SHIFT+F10
- >dir e: (you must see vhd file, if not change disk d:, e: …)
- run DISKPART
- (if not done on windows)
>create vdisk file=e:\vhd\win8.vhd maximum=30000 type=fixed - >select vdisk file=e:\vhd\win8.vhd
- >attach vdisk
- >exit
- on the screen with choice update / custom:
select CUSTOM - select unallocated space for installation and ignore warning message : next