Volume icon disappeared and shortcuts on the keyboard does not work properly!

Good afternoon people!

I've got a serious problem on my iMac. Some of my keyboard buttons are no longer responding. The volume button on the keypad (F10, F11 and F12) are not working anymore. This started an hour to another. Brightness buttons on my keyboard (F1 and F2) are having the same problem, do not respond when I press. Click with right button of the Magic Mouse is not working anymore too, when I need to use, I have to hold the keyboard "CONTROL" key for the menu to appear!

I do not know what may have led it happen. I tried resetting the PRAM, used applications like Clean My Mac, CCleaner and OnyX for trying to solve and so far nothing solves.

Does anyone have any tips on the horizon?

Sorry about my English!

Until next time