Check your laptops manual, some need a change in the BIOS for primary video, others might use a key combination to change from one or the other, might also be in the video driver package to set it to laptop or external or both screens
Check your laptops manual, some need a change in the BIOS for primary video, others might use a key combination to change from one or the other, might also be in the video driver package to set it to laptop or external or both screens