Well this happened when I upgraded to Natty. Not only seems I can't change my resolution to higher than 1024x768 but it appears at the left and using only 70% of the monitor's width.

I tried logging in but in ubuntu classic mode, and i was able to change it, but that trick did not work anymore. (May this be a compiz problem?)

Anyways, here is my /var/log/Xorg.0.log http://pastebin.com/Ew4wwLab

and lspci -nn | grep VGA:

00:02.0 VGA compatible controller [0300]: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller [8086:27a2] (rev 03)

I tried using xrandr for adding manually a resolution of 1280x1768 but without luck. Here is the xrandr output

Screen 0: minimum 320 x 200, current 1024 x 768, maximum 4096 x 4096
LVDS1 connected 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1024x768       60.0*+
   800x600        60.3     56.2  
   640x480        59.9  
VGA1 disconnected (normal left inverted right x axis y axis)
TV1 disconnected (normal left inverted right x axis y axis)
  1280x1024 (0xc6)  109.0MHz
        h: width  1280 start 1368 end 1496 total 1712 skew    0 clock   63.7KHz
        v: height 1024 start 1027 end 1034 total 1063           clock   59.9Hz