I have the Satellite A665 laptop. Same thing happened to me.
I tried what ever i thought of. Even putting a Music CD in the Drive hoping it would clear the Problem.
After putting in the CD, i Pressed the Play/Pause button on the Top row of buttons. (this is the row where the Start button is.
* After pressing the Play/Pause button, the Mouse pad lit up. It seems fine now. *
I hope this helps you !
thanks Tom's Hardware for this Site !