I was upgrading xubuntu. It was taking quite a while and I went away from pc. When I came back I saw a new desktop and there were no windows opened and panel didn't work too. Opening folders gave error that some file didn't exist (I don't remember exactly which)
So I decided to restart the PC and while it was turning off I saw the installation window and realized that the installation process wasn't actually finished.
Now when I turn on PC, after xubuntu logo there are only black screen, static text line on the top-left corner and cursor appearing and disappearing every 3 seconds. I can't even open tty.