Another way is to download the VirtualBox and install then if you have Linux CD or ISO you can start installing it with VirtualBox
This might be possible, but is definitely NOT the recommended way.
You don't want to have the VM and the Host-OS sitting between you and your hard drive. That just increases the risk of anything going wrong.
The most convenient (and probably also best) approach would be to use a live system (bootable from USB).
This way you'll be able to directly mount the drive and copy/work on it, without multiple abstraction layers in between.
There are multiple guides available on the internet which show how to create a bootable linux USB stick.
