This message was posted on behalf of Intel Corporation
I understand you have problems getting the computer detect external monitor. Let me help you on this matter.
You computer seems to have hybrid graphics, this means you are currently on Intel® graphics controller and Nvidia* card.
I recommend the following steps to try to solve this problems:
1. Please remove any graphics drivers from your computer by using Programs and features from Windows® Control Panel
2. Install the latest graphics drivers from Intel at https://downloadcenter.intel.com/download/27267/Graphics-Intel-Graphics-Driver-for-Windows-15-40-?product=86210
3. Download and install Nvidia* graphics drivers from your computer manufacturer's website.
Please let me know your findings.
I downloaded the right file from the page you kindly provided. I looked at the version of my current driver where I found and installed from DELL website, it is 184.108.40.20631. The version of the driver in INTEL website is 220.127.116.1135 which at least judging by the numbers, should be newer. But unfortunately as I try and install this files it shows an error which says:" Te driver being installed is not validated for this computer.Please obtain appropriate driver from the computer manufacturer". and the newest available on DELL is the one I already got.