You never described what exactly happened. Which desktop have you seleced? GNOME, KDE. Anything else? No desktop at all? Which displaymanager is running (in case you know this)? Is the Xserver crashing, i.e. you get a new login screen? Or do you see a blank screen? Anything else? >From the initial description it looked like you were logging into the Linux console and then ran startx. Which simply no longer works since a long time.