i have two external monitors connected to my Dell N7520 Notebook, one though the HDMI port, and the other from the VGA one. when they are connected separately, each monitor working as great as it should!
Problem is popping when the VGA port is connected same time with the HDMI. when i do that, Only the VGA monitor is working and the HDMI one is black screened.
when trying to apply "extend desktop to this display" to the HDMI one, i get: The display settings could not be saved. Please try a different combination of the display settings
e.g: when HDMI is connected and working perfectly, trying to connect the VGA one making the HDMI black screened, and the VGA to be working instead..
heres are the specs: http://notebookspec.com/notebook/4731-DELL-Inspiron-N7520-V560404TH.html