builtin trackpad and keyboard don't work except power key

I have MacBook Air 11"(late2010),OS X is Lion 10.7.5.

But Apple internal Trackpad and Keyboard do not work except power key.

Mouse and keyboard connected USB ports work very well.

Apple internal Trackpad and Keyboard are not listed in the USB devices list of

Apple system profiler.

Plesse tell me!

Why does only power key work?

Why do not Trackpad and other keys work?

Which parts are damaged?