GRUB

One day ago, I started upgrading my Ubuntu 16.04 to 18.04, after I see the update from website. The most diffrience betwen 16.04 and 18.04 is that the 18.04 use GNOME desktop rather than Unity. I had heard that the GNOME desktop is better than Unity, so I tried 18.04 for the new desktop. Unfortunately, after I upgraded my OS, I found that the GNOME desktop wasjust so uncomfortable. And after one hour I gone back to 16.04:(, and content of this article is about the problems I met while reinstalling the OS. ...