The Intel(R) Graphics Media Accelerator and Intel® HD Graphics support two active displays running on Clone or Extended mode.
However this is only supported when using two separate and physical video ports, not when using VGA splitters or similar cables. These kind of adapters will prevent the system from detecting the monitors connected, which most of the times results on only one monitor working through that cable.
In this case you would need to use an ADD2 card to add more video ports to your system, or use an external video card with more than one video output (keep in mind that using an add in video card will disable the integrated graphics).
Thank you Diego_Intel. You are correct. I appreciate your prompt and well-explained response.