LC, if you use a splitter, you are sending the same signal to 2 monitors, so you will get the same output on each. You may be able to resize them so that different parts of the desktop appear on different screens.
Look in the display adapter properties (right-click on blank area of desktop - click settings tab). If your display adapter supports 2 screens you will see a greyed out square with "2" in it; the main screen will have a "1" in it. If you see this, it means that the adapter will support 2 screens and you will be able to use both outputs separately.