The whole system suddenly restarted when I was watching video. After rebooting, the display has become blurred and out of focus. The interface becomes normal for around 2 seconds whenever that window is moved or active.
I had this problem when I used Ubuntu from the first time. It was solved by installing Gnome.
What causes the interface blur and how could I i fix it? The video card that I am using is from Nvidia, I don't know whether this relates to the problem or not.
I also suspect the Gnome is not working after the system crash. Can anyone explain how to check whether Gnome is working or not? And how to repair it?