Basically, the cable guy was a fuck up. Not only did he screw up my installation (by provisioning the modem that didn't work, and not the modem he actually ended up installing) but while he was there he had to take a couple calls where he got chewed out by his boss for screwing up other peoples' installations.
He left me with the internet not working, claiming that it was Earthlink's fault. Or, rather, claiming that it *was* working and that I had to install the [shudder] Totalaccess software before I could actually use the internet. It took a bit to install the software -- which of course was useless -- and by that time he was long gone.
Fortunately, there was someone halfway competent in the third cable tech support department I was transferred to. The first two told me that cable was plug and play, and that if the lights on the modem were all on, nothing could possibly be wrong with it. The third girl seemed to actually have the ability to run diagnostics, and said that the modem was provisioned, but she wasn't getting a signal from it.
"Maybe it's the wrong modem?"
"Try power cycling it."
"Still broken. You know, the cable guy had to install a second modem because --"
"Hold while I try my diagnostics again."
"Um... can you read me the serial number?"
"Okay... blah blah blah."
"Huh, you sure it isn't [first modem's MAC address]?"
"No, that's the MAC address for the first modem he tried to install, that didn't work, so he replaced it with a different one. This modem's MAC address is..."
Anyway, at that point it still took a long time, but she realized what the problem was and provisioned the right modem, and in the five minutes or so that I played around with it before finally heading to work, it seemed to be working.
So, hopefully, that'll be the last of the problems I'll have with it. Well, until the billing cycle comes around and I can see if I get double or triple charged. Oh, and I still have to figure out if my e-mail address that I want to keep is attached to the right account. And uninstall total-fricking-useless. I mean, access. The modem seemed to be working fine without it running at any rate.