I'm interpreting what he said differently.
rsymons,"on the mother board there are two ,two wire (red/black )plug ins. on the second plug in, the red wire goes to the power, but i don't know where the black wire goes. it's not a ground because i can measure voltage."
Were you referring to testing the black wire, or the connector on the board, with your meter?
If the black wire is disconnected from the plug you would see voltage on it, returning from the device receiving power, if the red wire is still connected to the board via the plug.