This has got to be Karma of some kind. I spend 11 years mocking corporate tech support and what happens? I fall victim to a variation of one of the CLASSIC "stupid user" scenarios...
As you may know, and as has been reflected by the very sporadic updates to this site over the last few weeks, I have been having difficulty getting my cable modem to stay online. For a long period of time it was up for 5 minutes, down for 5 minutes, up for 5 minutes, down for 5 minutes, interrupted by periods of hours (or, in one instance, DAYS) of not being connected at all. A call to my cable company's tech support line was encouraging, because the tech I talked to was able to detect strange power fluctuations from the cable modem, and she scheduled a guy to come over and take a look.
So on Tuesday the guy showed up, and had a look, and said he would try to replace the cable modem to see if that made any difference. And as he bent over to disconnect it, he said "... oh. Sir? I think I see the problem."
The cable modem, as it happens, is connected to a Linksys Wireless router, so that all our computers can access the net without all that pesky cabling. That wasn't a problem. The problem was that the Linksys Wireless router and the Cable Modem use power adapters with different voltages, and I HAD PLUGGED THE WRONG ADAPTERS INTO THE WRONG DEVICES.
"This," said the guy, "might account for those power fluctuations."
He switched the cables around, and I haven't had any connectivity problems since.
Boy, do I feel stupid.