As far as I know Virtualbox can only launch from the virtual-harddrive spaces that you have created for it. Those virtual hard drive spaces can dual-boot however. I have a windows / vector dual boot set-up on my desktop downstairs. On my laptop I have 4 different virtual machines accessing each their own virtual hard drive for, vl-light, kde-classic, soho6.0, and standard. With a newer computer and 4gigs of ram you can easily run 2 virtual machines side by side, each drawing from it's own virtual drive.