Ten minutes later, Leo received an email. Attached was a perfect screenshot of the error message. Below it, Nana Joan had written: "It worked! The computer wasn't broken. I just forgot to plug in the mouse. Thank you, dear."

He added one final tip: "If you just press 'Windows + PrtScn' together, the screen will dim for a second, and the screenshot is automatically saved as a file. Go to 'This PC' > 'Pictures' > 'Screenshots'—you'll find it there."

Then he remembered—she only wanted the error box, not her messy desktop wallpaper. "Better yet," he wrote, "click on the error box so it's the main thing you see. Now hold down the 'Alt' key (next to the space bar) and, while holding it, press 'PrtScn.' That only copies the active window. Then paste it the same way into an email."