use two connectors. Look as one when they are plugged in. For the two, they plug in such that the black leads are next to each other. No idea about three, so I'm wasting your time except to say email the Compaq [now hp] website and ask. I understand that they can be very helpful.
I have an old motherboard with an AT form factor. (Its a Compaq Presario 5220). I unplugged the power cord that connects the power supply to the motherboard. Does anyone know the general pattern to connect it. (There are three plugs that need to be connected and each are label P1, P2, and P3. Any help would be greatly appreciated.