Last night I updated my kunbuntu from dapper to karmic using the GUI (kynaptic). At restart kde was not starting, I ended up with my the terminal mode.

I diagnostic-ed it by manually starting the Xserver


I realized the system was complaining about the fglrx driver (I formerly installed with Dapper on my laptop dell D610) If this happen to you too, you may fix it by doing this :

Check first your graphic card name and chipset:

$ lspci -nn | grep VGA

First removes both -fglrx and -ati, and reinstalls the latter:

sudo apt-get remove --purge fglrx*
  sudo apt-get remove --purge xserver-xorg-video-ati xserver-xorg-video-radeon
  sudo apt-get install xserver-xorg-video-ati
  sudo apt-get install --reinstall libgl1-mesa-glx libgl1-mesa-dri xserver-xorg-core
  sudo dpkg-reconfigure xserver-xorg

Then reboot

At last edit the xorg.conf file

sudo vim /etc/X11/xorg.conf

Look for the above Section Device'' and change the Driver'' from fglrx to ati (I can’t be NOT radeon either). The ati'' driver is a wrapper that will load the radeon'' driver if possible.

Section "Device"
        Identifier      "Radeon 9600"

        Driver          "ati"
        BusID           "PCI:1:0:0"
        Option          "XAANoOffscreenPixmaps"

more here: