So I called Sam and proposed an exchange of favors today. I went down to his place where his computer still wasn't working correctly with his old external modem, looked it over, and led him to the store to buy a new modem. Things appear to be working correctly now, although Sam remains unsure as to whether the "Roper Effect" is in play. This would be one of those psychic phenomena where the computer only works when I'm there. We'll see.
Then we came back to my house where Sam helped me put up a ceiling fan in the office. It's much nicer up there now.