Leo says she should install the VirtualBox software in the same place she installs her other programs. She will install that first, then run it to set up a virtual machine. It will install the operating system from the ISO that she has, and it only will use that ISO once. So that can be located anywhere. In fact, Leo often puts ISOs on USB keys. The ISO is the operating system installer, essentially. Then, the virtual machine can be installed anywhere she wants. If she has a faster, or larger drive, she can put it there.