.. well you guys are right your video card has to support 2 monitors but lockon wont run on both of them. just one, your main one... and your second one is your desktop. what i do is i put ventrilo and my temperature stuff over there so i can see who is on ventrilo and what my temperatures are in game....
you enable it by plugging both monitors into your video card then you right click on your desktop go to properties then settings and it should be there but only grayed out...(if not restart computer with cables still plugged in) select it and then check the box that says extend my windows desktop onto this monitor.... and hit apply and BOOM second monitor.... i have used mine for 2 years now and no performance loss because the video card is built for it.