Macbook Air keyboard and trackpad not working

I have a refurbished MacBook Air 13-inch and for a couple months, the keyboard and trackpad have not been working. I cannot turn the computer on, the only time the keyboard and trackpad work is when I am in the log in screen. It always seems to work here, so I know there's still a connection between the keyboard and the actual computer. Whenever I press the power button while the computer is charged, the charger changes from orange to green for a second, but that's all it does.

Please help!