Jonny's questions

I have a problem with all GTK apps (evince, gedit, Firefox, gimp) not seeing my installed printer. When pressing Print, I can only choose Print to file, my printer is not shown. So I can not print PDF documents, websites...

In LibreOffice, the printer works.

How can I get the printer to be seen by the apps and print PDFs?

Some more information: It is a network printer (hp). When a document is printed from LibreOffice, the printer is shown for a few seconds as printer in the other GTK apps. Then disappears again.

How can I easily get tensorflow gpu running?

I tried to install the Nvidia driver (sudo apt-get install nvidia-390) for AI calculations on GPU in Ubuntu 16.04 and 18.04. The installation works, but afterwards python3 is not working and giving the error: "ModuleNotFoundError: No module named 'tkinter'", but of course tkinter is installed and can not be reinstalled. I have a notebook with GT 740M graphics card. Any ideas how to get the graphics card running and also python3 running?

To install the graphics driver I need to exit GUI / Gnome and go to the terminal. How can I do this in Ubuntu 18.04? Ctrl(STRG)+Alt+F1...F7 does not work, neither on the desktop, nor on the login screen...