Cannot use Nvidia card in Ubuntu 16.04

Hello I am trying to switch my GPU to GTX 1060 from Intel® HD Graphics (Coffeelake 3x8 GT2). I installed Nvidia driver and selected it active from “Additional Drivers”. After doing that I rebooted my PC but then I get “No discrete VGA device found.” Any solutions?

Please run nvidia-bug-report.sh as root and attach the resulting .gz file to your post. Hovering the mouse over an existing post of yours will reveal a paperclip icon.
https://devtalk.nvidia.com/default/topic/1043347/announcements/attaching-files-to-forum-topics-posts/

When I “sudo nvidia-bug-report.sh” it says “sudo: nvidia-bug-report.sh: command not found”.

Normally, it’s installed alongside the nvidia driver, did you uninstall it?

I did not uninstall it. And also I installed Nvidia driver with “sudo apt-get install nvidia-415”.

Maybe the paths are not properly set. Try
sudo /usr/lib/nvidia-415/bin/nvidia-bug-report.sh