Ok so I am working on this computer, and I just replaced the motherboard. The motherboard happens to be a Dell motherboard, and I can't get it to power on, even though I have the power switch in the right place (the power switch worked before). What I noticed is that in addition to the ATX plug in, the motherboard also had an AUX plug that looked like an AT style plug in. I had never seen anything like it because usually motherboards that have a secondary plug in have the little square plug in. Is what I am dealing with proprietary, or older technology? If the later is the case, what kind of power supply would it be?