Always test the laptop with some USB keyboard and mouse to see if this is a software issue. If the problem is the same on the keyboard then it's some blown OS issue.
The keyboard looks to run from 25 to 99 bucks, example at https://www.newegg.com/Product/Product.aspx?Item=9SIADG45V31630
Given this is 4 years old it's common to start to see keyboard failures. As to the touch pad, my advice is to get a mouse.
I have an Asus Q500A on Windows 8.1. Suddenly, the touchpad and keyboard aren't functioning correctly. I can't right click with the touchpad, and some of the function keys are unresponsive. I don't know what caused this or how to fix it. I already disassembled the laptop twice to make sure the ribbon cabling inside was secure and it is. Any help would be greatly appreciated