Yes I know this has been asked before. I tried the suggestions but nothing worked.
I know though that this has something to do with .net framework because here's what happened. I was trying to install the latest version of .net framework so I could use TunnelBear . But it was taking so long so I just cancelled it. After that, I've had problems when booting my laptop. Something about not being able to boot properly.
I removed the .net framework on the registry (an ignorant mistake. I didn't know it was important). Then the "gfxui has stopped working" started appearing.
So I downloaded the V4.0 of .net framework and successfully installed it and turned on the .net framework feature on windows feature on control panel. But I still get the error.