For awhile the 'e' key was only working about 90% of the time. Then it began working about 120% of the time, so I had to remap it to nothing, move the 'e' to the backslash, and plug in an external keyboard. The trackpad and all the rest of the keys were working just fine. I usually replace machines every three years or so anyway, so the key issue was just the trigger. Thank you for your advice. Do you think that might be the issue, given that the trackpad worked fine?