Give up. Accept that some people can't use a PC at all or at the current moment, they have other priorities and problems and can't focus, act and think coherently. Or that you could use your time to help much more people (those that are actually interested in learning).
Just phone the guy and say: "Look, I'm really sorry, I did my best but I have no idea how to help you. I though I knew how, but your situation exceeds my skills. If you want I can give you a list of companies that fix computers".
Then use your time for you, your family, your friends, your health, your knowledge, etc.