smartbopard should connect to laptop by serial port not vga port.
vga port on laptop connects to projector. there will then be a key combination on your laptop to have just laptop display, just projector display or both. (it is usually one of the "F" (Function) keys. You may need to push buttons on your projector to select vga input. and make sure you connect to "VGA in" on the projector.
Usually the only benefit of the usb connection between laptop and projector is to enable a wireless/RF mouse or remote control that may be supplied with the projector to control the laptop mouse function.