Whenever you are typing out stuff on your computer, keep saving your work at very frequent intervals. Otherwise, when an unexpected shutdown occurs, you will lose all your work.
I am ashamed to admit that, me, a qualified computer professional (with a Master's degree, no less, to boot) just now did not follow that crucial basic axiom of using a computer. And hence lost the blog post that should have appeared in this space. Learn from my example. Save, save, save!