I had got a laptop integrated NVIDIA GeForce GT 740M and Intel HD GPU, and everything worked fine on Windows 8. However, I am unable to connect it to a LG HDTV through the HDMI ports after upgrading to Windows 8.1 OS. I open the Devices > Second Screen and select Duplicate, the HDTV external Montior picks up no video signal.
Many users have reported the HDMI output not working issues after updating to Windows 8.1 from 8 with computers and those laptops, such as Asus NV550JV, Sony Vaio, Toshiba, HP Pavilion and etc. Trying high end HDMI cables and different televisions and projectors still can’t detect the external display. You could try the following tips to resolve the problem.
* Make sure you have installed the available firmware from Windows Updates, and the latest NVidia driver from your manufacturer website.
For HP devices, you could restore the drivers.
Type Recovery Manager from Start screen, and select it from the results. Click Hardware Driver Reinstallation > Next and then choose the original video drivers to install it.
* First it requires a wireless keyboard and mouse to make the control.
Open control panel, go to Appearance and Personalization > Display > Screen Resolution, and select the both monitors for display option.
You could also right click on the desktop to get the menu, and clcik the link with the graphics panel, then configure HDMI detection and the parameters with external monitor display resolution.
* If the above method are not working, you need to wait for the official solutions.