Internal laptop screen not detected when using Nvidia driver

Some similar thing happened to me. It turned out that it was caused by something in the /etc/X11/xorg.conf file. Luckily, there was a default nvidia config file I could use.

This solved my problem:

cd /etc/X11
sudo rm xorg.conf
sudo cp xorg.conf.nvidia-xconfig-original xorg.conf
reboot

Resetting the X11 config file (generated by default by the nvidia-config for 1 monitor only) fixed the same issue for me too:

sudo > /etc/X11/xorg.conf

reboot

Note: this is the same as the solution in the previous comment just because /etc/X11/xorg.conf.nvidia-xconfig-original is empty (zero) file in fact.

I simply deleted /etc/X11/xorg.conf and /etc/X11/xorg.conf.nvidia-xconfig-original and rebooted. It worked for me!