If the HDMI / VGA cable and the touch USB cable is connected and still the touch is not working kindly perform the steps mentioned below.

  1.  Open Control Panel


      2. Select Hardware and Sound > Pen and Touch > Change tablet pen settings

    3. Under Touch please check "Use your finger as an input device" and "Enable multi-touch gestures and inking".

 4.  Restart your computer and now the touch functionality should work.