My computer isn't dead. As far as I can tell, there is absolutely nothing wrong with it anymore. The hard drive not mounting was due to a corrupted filesystem which happened because when I moved the computer to the bedroom when the wireless wasn't working, the wall socket the power strip was plugged into was loose (most of the sockets in our apartment are way loose) and next to the bed, which, when jiggled, cycled the power several times in a row.
This is a bad thing for computers... Mac OS X's filesystem is journaled nowadays, which is supposed to keep corruption from happening, but I think one of those subsequent power cuts happened when the journaling was fixing itself. The computer wouldn't start up, and when I started it via CD it couldn't see the hard drive. Disk Utility could see the hard drive but couldn't even tell how much space was used/free on it and couldn't repair it or even check it for errors.
DiskWarrior came to the rescue and rebuilt the filesystem without any losses. This is the third time in my life it's saved my bacon. So, this is a happy things post. I'll have to buy a new wireless router (since my computer is verified to work here at Brandon's and shows very good wireless signal strength), but I've hated that router for the last several years and will be happy to replace it. I'm thinking something with remote backup capability this time.