Comment 76 for bug 107115

I just got done installing Hardy Heron on my laptop and began to experience the same problem. My laptop came equipped with an ATI 9600. After doing some successful logging in and out to get my system configured with its various users, I noticed that a notification box appeared at the top of my screen informing me of some new and nifty proprietary drivers just waiting to be installed that were pertinent to my video card. I clicked on it and went through the installation of the ATI accelerated graphics driver.

After installing this driver, I rebooted my system. From there I went back into my root account to finish configuring the system and cleaning up. I then hit the CTRL-ALT-BKSPC to go back to the X login screen. I experienced a black screen and my system froze up. I attempted to move over to one of my terminals using CTRL-ALT-F2 or CTRL-ALT-F3. Both of these endeavors were unsuccessful. I had to manually power the system down and reboot.

I was able to isolate the issue to the ATI accelerated graphics driver that I had installed. The only fix that I can suggest here is to disable and uninstall the driver through System>Administration>Hardware Drivers. After doing this, reboot your Ubuntu box and everything should be fine. You may lose a few bells and whistles in the process (i.e. 3D acceleration, eye candy, and 2D stuff).

I'm fairly sure that it's the ATI driver creating the problem and crashing X. I hope that this helps someone.