How we can build virtual desktop screen ???

Hi all,

  Anybody knows how we can build "virtual desktop screen" for
WIN31/WIN95? By "virtual desktop screen", I mean that the desktop
upon which icons, bitmaps, windows can be placed and is controlled
by programming is larger than the screen which is what actually seen
by us. We can pan screen views within the desktop domain. I know
that ATI has utilities for such purpose bundled in its VGA cards.
  Many thanks in advance.