You run it on the Windows VM not on the host.
However if you really want to mount the .VHD you can from within Windows 7 (not previous ones)
You go to start > right click on computer and click Manage.
Then You go to Disk Management under Storage.
Then go to the Action menu and Attach VHD
Choose the path to your .VHD file and it will mount it as a drive, you can then select the windows directory on that drive.
Or it could be after a windows CD iso, in which case you download it from your technet account.