I don't have 4 screens. Only 3.
Screen 1: laptop itself (18.4 inch, 1920 x 1080)
Screen 2: VGA port from the laptop, 23-inch mon, 1920 x 1080
Screen 3: Tritton UV200 USB-to-DVI adapter, 23-inch mon, 1920 x 1080
You can hook up a second USB-to-DVI adapter to drive another monitor to...