Sorry, forgot to say:
when i turn the computer on, everything is running, i heard a sound, and two of the CPU_Phase LEDs are on.
i do not think my motherboard is defective at this point, because it still seems responsive (lights are on, etc).
update: i forgot the system speaker. after i plugged it in, and turned on my computer, i heard 3 long beeping sound. i changed the memory to another slot, and now i get 1 long, and 2 short beeps, which apparently means video errors. what should i do?