Actually the guy in the article is nowhere close to being an expert. He seems more like grandma.
Doing this for a client, shows that he should not have done this in the first place.
First thing you do, when doing maintenance is to build a checklist. Especially if doing for a client. Never experiment with a clients computer. Especially installing Linux on a computer of a client that cannot maintain it. Linux is not for everyone, and certainly not this guy.