ERROR After downloading latest NVIDIA Driver Blank Screen/Not able to display GUI problem. Geforce GTX 1660Ti Dual Boot with Windows /Ubuntu 18.04.5

Everything is started with trying to upgrade NVIDIA driver to the latest version in Ubuntu 18.04.5 Desktop. After purging all nvidia related packages/files, I tried to download the necessary driver with several ways including .run file from the NVIDIA drivers’ website, Software & Updates and from the terminal(apt-get install nvidia-driver-xxxx). However, in every combination, I faced with the same issue. I couldn’t manage to boot into gui and stucked at black screen with OK messages. However, If I remove all nvidia packages, I am able to boot into GUI which is gdm3. I tried lots of methods that written on the web but I couldn’t manage to solve the problem.

Also, I get this error. Maybe it is related.

Finally, here is my nvidia bug report. nvidia-bug-report.log.gz (321.4 KB)

You still have your Intel igpu enabled, so Ubuntu thinks you’re on a laptop running in intel mode with the nvidia driver blacklisted.
Please remove the ‘nomodeset’ kernel parameter and run
sudo prime-select nvidia
and reboot