You'll be thrilled to hear that after I emailed Time Warner questionning whether their support staff actually have pulses (and, y'know, heartbeats, brains--the whole shebang), they responded with these immensely helpful instructions.
1. Check my TV reception. (Um, thanks. We tried this on the day of installation. TV reception's fine.)
2. Check all the connections for your cable modem. (Hey, there's an idea. Like the three technicians who've been out might have missed a loose connection when they installed the thing. Crap, now that I think about it, why should I have trusted their expertise? Not that I haven't had all the cables in and out several times, so I think we got that one covered.)
3. Reboot the cable modem. (What am, I a rookie? That's, like, number one on the troubleshooting hit parade.)
4. If the above doesn't work, contact Time Warner's Broadband technical support line at ....
blah, blah, blah. You just KNOW that's my favorite one, right? The one where they hang up on you after you go through two minutes of punching in answers to recorded questions?
My response to their latest communication was to, once again, point out that if a human being is reading the entire email, her or she should be coming up with a different response. I ended it with an invitation to just admit they don't have a solution and that perhaps I should physically remove the equipment, dutifully return it to Time Warner, and go back to being a dial-up customer of Earthlink.