I don't often call myself an idiot. I work hard to avoid regret and usually feel enough paranoia while working on computers to be more careful than I need to be. However, I do remember a few times when I got myself into a ridiculous, avoidable jam on a computer and muttered some colorful things to myself about my own lack of wisdom.
When faced with a misbehaving computer, many optimistic people have an overwhelming urge to play the odds to fix their computer. They try all sorts of random things on the screen - clicking through multiple dialog boxes and changing setting after setting all while hoping to discover some checkbox or button that makes the problem go away. This is called a reckless repair. If it works, luck was involved. The most frequent service request I get is from clients whose reckless repair not only failed, but it made the original problem worse. These are victims that "knew enough to be dangerous."
The problem with reckless repair attempts is that multiple mouse clicks and setting changes add up quickly and can lead to an uncomfortable point of no return - unless your memory is fantastic. If you diagramed all the clicks and changes made to a computer during a frantic mouse-clicking repair attempt, you'd end up with a fairly complex flow chart of changes that could challenge even the best memory.
The urge to grab a mouse and just "go for it" is strong and I'm guilty of having it too. Taking written notes on each step that I take to fix a computer is as unbearable as reading the manual before playing with the cool new tech toy whose buttons seem so intuitive.
Fortunately, there is a simple safeguard that isn't as excruciating as scrawling each troubleshooting step onto paper. It's called a screen shot. PC's have a button, usually on the top right side of the keyboard, that says PrtScn. Press it and the computer captures an image of whatever is on your screen. On a Mac, press the Command, Shift and 3 keys all at once and you'll hear the sound of a camera saving your screen to memory. Open up your favorite image editing program and you can paste the image into the program and save it as a file.
If I have any concern about remembering the sequence of changes I'm about to make on a computer, I'll grab and save screen shots along the way. I save each screen image as a numbered file. If I get stuck and want to undo my steps, I have a set of pictures that can lead me, like a trail of blessed crumbs, back to where I began. It keeps me happy with myself and keeps my reckless repairs reversible.