Dragons Lair is as i know not released yet.
It will be released under the Name Dragons Lair 3d,maybe you have Siedler 4 there is a Intro from Bluebyte about the Game.Really amazing graphics.
The Games you mean from Digital Leisure are rather old.
But still great to play.
You can download them from the Home of the Underdogs,there are hundreds of realy old and great Games.
The link is:
www.theunderdogs.org or www.classic-trash.com