Well, it seems the voltage is indeed dipping too low. Last night, the desktop running in the other room shut down and restarted itself again. The server was off with its power cable removed, eliminating it as the cause of the problem. I then grabbed the Kill-A-Watt meter and measure the voltage from the outlets. I got different readings but the average was 103V. I checked the outlets in other rooms, and they were normal 116-118V.
Does anyone know how I can fix this problem or what the cause is? It does not seem to be happening all the time, and only presents itself maybe once or twice a week.