Since your computer has two graphics controllers then the generic graphics driver we provide will not work properly in that computer. The computer manufacturer provides a special driver that has been designed to work with both graphics controllers. I recommend contacting the computer manufacturer in order to get a graphics driver update and more advanced troubleshooting steps for this issue.
sorry for the delay.
thank you for his answer.
therefore have I to contact Acer to get a special driver ??
can' t I disable the management of HDMI from Intel graphics and delegate this work to Nvidia graphics ??
thank for your help.
Depending on how the computer is configured then you will be able to use one graphics card or another. Acer can help you as well checking how to use one graphics card or another.