Well, my PC is fixed, sort of. The problem turned out to be the seating of the processor, which was of course my own fault. The box now runs fine, and I’m typing this post on it.
Unfortunately, my monitor appears to now be dead. D-E-D dead. I called Acer and put in a repair request; Monday I’ll ship it to Texas and hopefully get it back within 10 or so days in working order. In the meantime I have stolen Mrs. Ardwulf’s monitor. She’ll get it back whenever she needs her PC, of course, and I will be banished again to the accursed laptop.
This very evening, however, I have managed to play some Allods Online and Team Fortress 2. It’s good to be back, even if it’s not quite full-time just yet.