No sound on my Asus Transformer I have two problems : 


my device was dropped to the ground (not by me) and the power button does not work anymore. I use the keyboard to wake up and suspend it.
sometime, the sound does not work anymore, and I cannot reboot it to make it run again.


The device is not rooted (no reason), run Android 4.0, how can I handle it?
You said:


  my device was dropped to the ground


and


  sometime, the sound does not work anymore


This would very much seem to boil down to a hardware problem. The only way to "handle" it is to repair the hardware. You can start with the Asus repair page.