How many video cards connect to the mobo with wires? They just plug in to the slot.
Well, the last one I connected which was a 9800 Pro haha. Did you try ati tool and it still didn't work? What card is it?
Edit: Oh I see you have a 1950Pro, I have an x800gto in my computer at the moment and I can read it's temperatures from ati tool. Did you go to settings - temperature monitoring and enable it?