A desktop psu powering a LCd monitor? how does that work?
till the early -90s it was common for the psu to power the (CRT) monitor as well. I'm sure my 386 computer did it, not so sure about 486dx4.. it might have shifted to the modern setup.. Likely it just routed the mains voltage through to an outlet for the monitor 3pin plug
BAsed on this, it sounds like op's system is really old, so there wouldn't be pcie slot in the mobo for the 5570 anyways... probably just some ISAs and PCIs...