Hello again. I powered up the two OK computers, got them warmed up, and then powered up the modem. Both auto-installed as normal. So, grabbed a fresh coffee before firing up the third computer. Moments later, auto-install chimed in as it is supposed to. I'm thinking the "repair" must have fixed the problem, but I'm still going to watch it closely for the next couple of weeks.
This is for Tech's response; Do you still want me to upload the log files? Let me know.
Thanks all for the help. If it decides to act up again, I'll be back.