How do I adjust the resolution on a Dell GX620?

Hello I was running Ubuntu 10.04 on a desktop Dell Optiplex GX620 with onboard graphics Intel 82945g (945G), and even then I had to use xrandr to add mode 1280x1024 and edit the files in /etc/gdm, but it worked.

Support for Ubuntu version 10.04 is at an end and I was always getting reminders of it, so I downloaded ubuntu-12.04-desktop-i386.iso burnt the cd and did a clean install of ubuntu 12.04 not a distribution update, now maximum resolution is only 1024x768. I have updated the kernel now to version 3.5.0-10; however, there is no gdm folder in /etc, there is no xorg.conf file in /etc/X11 folder, and when I run xrandr I get the following:

jo@jo-Lin:~$ xrandr
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 640 x 480, current 1024 x 768, maximum 1024 x 768
default connected 1024x768+0+0 0mm x 0mm
   1024x768       61.0* 
   800x600        61.0  
   848x480         0.0  
   640x480        60.0   

When I run cvt I get this result:

jo@jo-Lin:~$ cvt 1280 1024
# 1280x1024 59.89 Hz (CVT 1.31M4) hsync: 63.67 kHz; pclk: 109.00 MHz
Modeline "1280x1024_60.00"  109.00  1280 1368 1496 1712  1024 1027 1034 1063 -hsync +vsync  

Then I tried xrandr again several times:

jo@jo-Lin:~$ xrandr --newmode "1280x1024_60.00"  109.00  1280 1368 1496 1712  1024 1027 1034 1063 -hsync +vsync
xrandr: Failed to get size of gamma for output default
jo@jo-Lin:~$ xrandr --addmode default 1280x1024_60.00
xrandr: Failed to get size of gamma for output default
jo@jo-Lin:~$ xrandr --output default --mode 1280x1024_60.00
xrandr: Failed to get size of gamma for output default
xrandr: screen cannot be larger than 1024x768 (desired size 1280x1024)
jo@jo-Lin:~$  

Referring directly to your question, No. I am running 12.04 on a desktop right now.

The problem lies within your graphics drivers. First, consult your manual or computer specifications to find out whether your graphics card or graphics adapter is ATI(or AMD), nVidia, or Intel.Search for Terminal in the launcher. Then, type exactly and press enter:

sudo apt-get update

The next command will be run when you are again given a prompt. It will depend on what type of graphics card you have. If it is Intel, run:

sudo apt-get install mesa-utils

For nVidia:

sudo apt-get install nvidia-current

For ATI or AMD Vision:

sudo apt-get install flgrx

Let the command finish and then reboot.