I have a 13" Macbook Pro laptop and the mouse of the trackpad works just fine but the bottom right hand corner and bottom left hand corner clicks doesn't work. They were working just fine last week and someone messed with it and now it doesn't work. I went to trackpad preferences and under Two Fingers the only preference I can change is Secondary Tap the rest is just a list. Three Fingers and Four Fingers I can not change any preference there as well. How can I get it so that the preferences can be changed?