What can you do if your Ubuntu display screwed up

When I upgraded my Ubuntu Linux in my laptop from 8.10 (Intrepid) to 9.04 (Jaunty) using the "Upgrade to 9.04" option in Synaptic Package Manager, it didn't go smoothly.

After the packages download, upgrade, cleanup and restart, the login screen can't show up, and it jammed up in a distorted screen. My first tought was that the display driver or setting was not working well with the display hardware of the laptop.

Luckily, I managed to fix the problem within half an hour. And here is my solution:

• Press the Esc key during Grub bootup to bring up the kernel menu.
• Select the 2nd option "Ubuntu 9.04, kernel 2.6.28-11-generic (recovery mode)" to go to recovery mode.
• When the Recovery Menu show up, you can try to select "xfix - Try to auto repair graphic problems". However this didn't work for me.
• Therefore, I had to try another way and selected "netroot - Drop to root shell prompt with networking". I think you can also select "root - Drop to root shell prompt" as well.
• Key-in the root password, and you will enter to the root's shell command prompt.
• Key-in this command to manually configure the Xorg-server settings: "dpkg-reconfigure xserver-xorg".
• You will need to configure for the input devices (eg. keyboard) as well as the output devices (eg. display and monitor).
• When you get back to the command prompt, key-in "exit" to end the shell session and go back to Recovery Menu.
• Now, select "resume - Resume normal boot".
• If the display problem is fixed, you will see a beautiful reddish login screen with a stylish 3D Ubuntu logo on the bottom right.
• Welcome to Ubuntu 9.04 (Jaunty Jackalope).