Q: Q: Are you sure you want to shut down your computer now? Message

I Have an older macbook Air and I have researcherd this problem and it is usually the power button sticking from what I've found. Well my comp is doing the same thing but if I keep my finger on the mouse pad the msg never pops up. My comp will stay on for hours as long as I keep moving my finger on the mouse pad. I know this because I recently updated to the new iOS and had to keep my finger moving the whole entire time or the msg would pop up n my comp would shut down. Another unique thing about my Mac air is that the power button still works. I can turn the comp on and off with the button every time. And when the computer is on if I haven't seen the msg yet and press the power button I hear a chime like the computer sees me pressing the power button. Has anybody had this issue with any luck fixing it?