Not everyone has to be tech-savvy. However, the situation you find yourself in with your friend Nelson is starting to weigh you down, as is very evident in this post.

I think Nelson has told himself that he 'can't do this things' and has locked himself into that mindset. This could be due to his low self-esteem or the fact that he always has you on hand to help him.

Next time he asks you for free tech-support - ask him to take a piece of paper and pen and note down step-by-step what needs to be done, as this is 'the last time you will help him with this particular problem'. Also encourage him to use his browser and ask 'uncle google' questions.

I know this may seem like a drastic move, but I know from experience that such friends start to annoy us more and more after some time. It can all end in a big brawl when your ocean of patience finally dries up. Besides - the guy is a grown man, he needs to learn independence.
Great that you are patient and helping him, I hope you manage to keep this relationship healthy.... for both of you:)