It was like magic. i have watch the paradise example on an old laptop which does not have hardware 3D accelerator. Does this mean that when i develop a 3D game in unity3d it would run also on machines without 3D hardware accelerator? Thanks
Yes, Unity can run on quite low hardware - it was designed for that. But in order to run on old hardware you have to make sure that you don't use too many vertices and very complicated shaders and so on.
It is likely that the laptop was running some form of integrated graphics (Intel GMA series). This is still using a hardware accelerator, but you would be hard pressed to find a computer made in the last five years (or longer) that did not have at least some form of integrated graphics acceleration, and thus able to run Unity games.