Ubuntu 18 login screen issue

I have an external screen which was working fine. After the last restart, I have login screen on external screen only. After login, I only have laptopb screen and the external screen is black.


To solve this problem for login screen this helped but only for having main screen works for login and working.

https://askubuntu.com/questions/1043337/ubuntu-18-04-login-screen-display-settings/1043627

CPU tempreture is high

After installing Ubuntu 18, I found that cpu fans are working all the time no matter how I use the computer.
I could have see the temperature of the CPU with "sensors".

To install "sensors" on Ubuntu 18:

• "sudo apt install lm-sensors hddtemp"
• Then to start the detector, you run "sudo sensors-detect"
• Finally the command for seeing cpu temperature is "sensors"

Laptop display is not detected

After updating nivida driver to 415, I could not see the laptop display. I searched alot but a simple solution from here helped me.

I only needed to remove /etc/X11/xorg.conf and restart the computer. It detect the display and rebuild the config file.