The CMD commands for VirtualBox works even I've installed VirtualBox on "C:\Program Files\Oracle\VirtualBox\" and the VM was created on an external HDD?
MB: HP 805A (XU1)
CPU: 3.20 GHz AMD Pro A8-8650B R7
GPU: AMD Radeon R7 1 GB
RAM: 8 GB 1600 MHz DDR3