Background: Installing Ubuntu 8.04 (Hardy) on a Dell Latitude C400. The built-in video card uses an Intel 830M chipset.
When I installed the Hardy Heron, it set my display resolution to 800x600 and refused to give me an option to make it better.
Resolution: The problem was solved by editing the xorg.conf file. Below are the details.
The xorg.conf is located in /etc/X11
Wise man say: Backup the xorg.conf file before editing. Why? If you screw up your OS, the commonest one might be a gdm error or something when you restart, you will be able to simply go to the character based shell(no GUI X Server) and put your backup xorg.conf file back into play.
sudo cp /etc/X11/xorg.conf /etc/X11/xorg.conf-backup
sudo gedit /etc/X11/xorg.conf
Once inside the config file, I removed the "vesa" option under the 'Device' section. After saving the config file and re-booting, BAM! I was presented with a screen resolution of 1024x768.
Note: In addition to the above, user Charlotte Gonella had to turn off video scaling in BIOS.