I recently bought a Apple Mac book Air ultra portable laptop, I installed windows 7 OS in my laptop, along with the other hardware specification of my laptop are like, Intel core2 duo processor, 3 GB RAM , 456 GN hard drive along with this NVIDIA GEForce graphical interface. I mainly use this machine for gaming and some of the other entrainment purpose likes to watch movies and other video clips. For that I installed KMPlayer. But suddenly after install that, it is not running correctly. Also there is no sound out in my machine; I tried by default windows media player, which is also not giving any sound. I am very new user of this machine, so I am not having such information regarding all functionalities, so I am here for getting some suggestion regarding this issue. Any input will be appreciated greatly.