I just took some time and tested VirtualBox. Not only that DOS does not work well with it, but Win9X do not work good as well.
They will boot fine, but you will struggle with sound and video settings. (16 colors and lowest resolution) Funny enough, WinNT will work fine without problems. :laugh: (it was always hell to set it up on real computers
)
To emulate DOS/Win9X use VirtualPC. Older pre-microsoft version used to come with pre-installed DOS. :amused: