Fan twitches and LEDs blink when computer is plugged in
I searched around the Internet some more and I found the problem. The connectors for the LEDs and buttons from the front of the case were connected backwards.
The motherboard clearly states which pins are positive and negative, but the connectors don't. They do, however, have a little arrow near one pin. Based on how some other connectors attached, I assumed that the arrow was for the negative pin. It turns out that is for the positive pin. I switched everything around and it works nicely.
My guess is that the actual problem was caused by the power and reset switches being plygged in backwards. I don't know how this actually caused the problem, but the computer essentially acted as if it were repeatedly being turned on for one tenth of a second and then off for half of a second. This leads me to believe that the power and/or reset buttons caused the problems.
So, the lesson to be learned is that when there are arrows on the connectors, they are for the positive pin. Ideally, they would just use plus signs, which would be a lot more obvious.