Well we know you have the Asus Sabertooth motherboard but that's it , How about some more info or are we supposed to guess.
Meanwhile turn off and unplug your computer , then take the video card out of the slot and switch it with the card in the first slot , putting both cards back in and making sure that they are both seated all the way into the socket. Then plug the Pc back in and turn it on and see if that changes anything.
Thanks for the response - albeit, sarcastic ...The problem turned out to be the power supply. I have, in the past 30 years of being a PC enthusiast, learned a thing or two. The question I was asking, was based on a couple of remarks made by users on other forums saying that the SLI was not functioning on this board. The timing of my reading these remarks and the second graphics card not working. I will ensure that I offer more in the future so as not to insult or irritate others.