Tracking down problems with a computer is usually a multi-step process of developing conjectures that lead to hypotheses and eventually to a valid theory. The first conjecture is sometimes right, but more often it's not. I'll describe a recent puzzler. In Short Circuits: Ransomware may be less of a threat to individuals than it used to be, but "less of a threat" doesn't mean "no threat". We still have to be cautious. • Firefox's market share has dropped from 30% a decade ago to around 7% now, but the browser still has loyal advocates -- and with good reason. In Spare Parts (only on the website): A global computer chip shortage is creating havoc in the automotive industry and elsewhere, but missteps by car and truck manufacturers have made the problem worse for them. • I found a picture of what was probably my first portable computer from 1988. It's on display. • Twenty years ago: PC Expo had just concluded. The dot-com implosion made the show a lot smaller, but darker times were coming.