Why have my trackpad and keyboard stopped working?

I have never damaged my laptop. I’ve never spilled anything on it or dropped it, and I’m careful to keep it nice because it was very expensive and I cannot afford expensive repairs. However, when I turned it on the other day, the keyboard and trackpad had stopped working and I couldn’t log on. I looked it up and used different keyboard combinations that have worked for people in the past, but nothing helped me. The next day they randomly worked again, and now they’re back to not working. Is there anything I can do from home to fix it so I don’t need to take it anywhere?