My laptop screen is showing black screen most of the time, last week it worked twice only. I have formatted the laptop and install a fresh copy of Windows and updated the Intel driver to the latest update using Intel tool. I noticed that in the display section of Intel configuration window it doesn't recognize the laptop screen as attached while it recognizes the external screen only when connected as attached. I have attached the laptop configuration as well.
But you said "and updated the Intel driver to the latest update using Intel tool. ". This means you are using the Intel driver, and not your manufacturer's drive.
Whatever the case, support for your laptop comes from your laptop manufacturer. Please contact them for support.