Black screen after changing graphic card

[ele]

A few days ago after updates that show my computer display is laptop and that changing screen size no longer has black border around I notice that nvidia icon is gone and instead of it is red X icon. So today I tried to change drivers under Additional Drivers to one bellow the latest one I was using for NVIDIA GEFORCE 840M and when I log off all I got was black screen I tried to restart pc and I could see Ubuntu MATE logo and then it goes on, because I could hear the login sound, but I only get black screen.

I tried to follow wolfman tutorial How to install graphics card drivers in Ubuntu but I’m not sure how to get to Advanced Settings. If I press Ctrl + Alt + F2 " and then “Ctrl + Alt + Del” it restart my pc back to a desktop. Also another problem I don’t have network cable connection only wifi.

Can someone help please? What should I do?

[wolfman]

When your laptop boots, press the “Shift” key and then you should see the Grub menu, select the 2nd option then the 2nd option again but you will need to borrow a network cable for it to work correctly.

The other option is to boot into recovery then select “root” and remove the Nvidia package you installed and then reboot and see if you have a more or less normal desktop!.

As an example (replace “nvidia-304” with real package name!):

sudo apt-get remove nvidia-304

[ele]

Well I left laptop running yesterday for few hours and went on the old one and then when I came back I swipe my finger on touchpad and my desktop appear I don't know how is that possible or why trough.

That's the one I had problems with

I could then change back to the one I used before, first one one the photo that says proprietary, tested.

I will be more careful in the future, but I'm still wondering why I got red X where there should be NVIDIA or Intel icon on top right panel. When I hover over it says Active graphics card: unknown.

Thanks @wolfman will have to save this one for later if/when I need it.