The Charter people are suggesting that I reformat my hard drive (sigh), and if I do that, I have a friend I'm going to get over here to do that, because that's not something I'm fooling with by myself. The computer itself suggested that I "disable BIOS shadowing and caching," which does sound like it would free up the mystical "quota," but I can't figure out how to do that, either.
So if you don't hear from me for a while--or get any linkspam--you'll know it's gotten worse.
Oh, and
ETA: Okay. Commenters are suggesting that the wifi software that the Charter guy came over and installed has caused a memory leak, which is sounding right to me, because the problems started the same day, I've never had these problems before, I didn't go anywhere weird or dangerous on the internet to pick up a virus, and I have two overlapping antivirus programs running. Here's my question: how do I stop the memory leak or debug the Charter software?