When I hit Alt+A to animate the smoke simulation, I just get the particle effect without seeing the smoke. As you can see from the screen shot. I am now using 2.67b. Can somebody please tell me why it's happening as every time I wish to see the changes I have made I have to render the scene which takes a long time and is slowing me down.
As you can see from above left (blender 2.67b) when I hit Alt+A no smoke appears in the simulation. The image to the right with smoke is done with blender 2.62,