FATAL: No bootable medium found! System halted.

[MagicManTyler]

Once hitting start on the virtual box manager, the machine begins to boot up, and then goes to what looks like a command promt which i cannot type into, displaying "FATAL: No bootable medium found! System halted."

[mpack]

It means what it says - there is no bootable disk attached to the VM.

VirtualBox creates virtual hardware. You have to install the OS yourself, typically from an ISO image. See chapter 1 of the user manual.