After updating, GUI will not work, shows black screen

SUSE Linux Enterprise Desktop 11
SUSE Linux Enterprise Server 11
SUSE Linux Enterprise Desktop 10
SUSE Linux Enterprise Server 10

The graphics are not working on the machine.  It usually displays a black screen.  Some of the following errors may be observed.

In /var/log/Xorg.0.log

Fatal server error: no screens found

On the screen:

gdm[4081]: WARNING: GdmDisplay: display lasted 0.153522 seconds
gdm[4081]: WARNING: GdmLocalDisplayFactory: maximum number of X display failures reached: check X server log for errors
Failed to start the X server (your graphical interface). It is likely that it is not set up correctly.

The sax2 utility can be run directly from a command line to probe the monitor for the appropriate settings and allow changes to be made prior to the graphic system being loaded. This is the most reliable way to configure your graphics card and monitor.

1. The system will need to be brought up in runlevel 3 (text only mode) rather than runlevel 5 (graphics mode). To do this reboot the system and when the GRUB boot menu is displayed type the number 3. The 3 will show up in the Boot Options below the menu selection. Press enter to boot the system. When the text Login: prompt is displayed enter root and then the appropriate password.

2. Optional: Backup your current configuration (if it is working at all) which is held in the /etc/X11/xorg.conf file.

cp /etc/X11/xorg.conf /etc/X11/xorg.conf.mybackup

3. The sax2 command will need to be run on console 0, but there is an easy option that may work and is worth trying first:

sax2 -r

3a. This will load the card and monitor configuration program attempting to discover the correct settings. A graphics screen should be displayed with 3 options. Select "Change Configuration".

3b. Verify that the Monitor is selected correctly. If not, change it.

3c. Verify that the Resolution and Color Depth settings are correct.

3d. When you select OK you will be given a chance to test the settings. Test it. If it looks good then save the changes and exit.

4. If step 3 worked for you then back at the command line enter the command:

init 5

This will startup the graphics system and display your normal login.

If step 3 failed or did not give satisfactory results then proceed with step 5.

5. In this step we will use the sax2 command to switch to the generic VESA driver.

If you attempted to start the graphics system in step 4 you will need to get back to runlevel 3 by running the command:

init 3

Press "Enter" after it runs to return to a command prompt.

For the following command you must know the name of the driver to be used for your card as mentioned above and it must be installed. For this example I will use the ATI proprietary driver "fglrx".

sax2 -r -m 0=vesa

Note: the 0=vesa is the numeral zero and not the letter O.

This command should bring up the same graphic interface explained in step 3. Please follow steps 3a-3d above.

6. Once complete return to the graphic Desktop by running the command:

init 5

Or reboot the system.

The /etc/X11/xorg.conf file has changed or become corrupt. The video driver itself may have been damaged as well.