Patrick wants to add a second monitor to his computer. Leo says it's easy to do if the video card supports it. If it just has two ports, one analog and one digital, then it may not support two. A new video card will probably be required, and even a $50 card will support this.
Web956 says that Patrick's card will support two displays. Leo suggests digging into the monitor settings. This link from the chatroom says that it doesn't work too well, though.