Thanks for your response!
I've tried reseating the processor twice, as well as switching RAM slots. Right now I have both chips in the blue slots.
I have two power cables running from the supply to the boad -- the main cable, as well as the 4 pin cable plugged in just above the processor.
I'll mess around with the RAM again when I get home later today, but assuming that does *not* fix the problem, do you have any other suggestions?