Recently I downloaded Ubuntu 10.04 and upgraded Ubuntu 9.10 to 10.04. I had tried the Live CD first to make sure that video and sound will work. After upgrading to Ubuntu 10.04, for some apparent reasons it did not liked the ATI driver and it wanted to run in low graphics mode. I had to restart X on each boot. To fix the problem I went to google to search for any available solutions and I found one. So, here is what worked for me:
- Open Terminal, and run the following command: sudo apt-get purge fglrx-modaliases fglrx-amdcccle fglrx-kernel-source xorg-driver-fglrx xorg-driver-fglrx-dev
- Now run the following command: sudo rm -r /etc/ati
- Now run: rm /etc/X11/xorg.conf*
- Now run: rm -rf /usr/share/ati
- Now open Synaptic and install fglrx package. If the installation fails then run sudo apt-get install -f in a Terminal window.
- Now run the command: sudo aticonfig --initial
- Now reboot your computer and the graphics should be working now.
Here is the original link to the solution: http://ubuntuforums.org/showpost.php?p=9062521&postcount=158