xrandr
Screen 0: minimum 320 x 200, current 1024 x 768, maximum 32767 x 32767
VGA1 connected primary 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1024x768       60.0*
   800x600        60.3     56.2
   848x480        60.0
   640x480        59.9
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

cvt 1440 900 60
# 1440x900 59.89 Hz (CVT 1.30MA) hsync: 55.93 kHz; pclk: 106.50 MHz
Modeline "1440x900_60.00"  106.50  1440 1528 1672 1904  900 903 909 934 -hsync +vsync

xrandr --newmode "1440x900_60.00"  106.50  1440 1528 1672 1904  900 903 909 934 -hsync +vsync

xrandr --addmode VGA1 1440x900_60.00

xrandr --output VGA1 --mode 1440x900_60.00

xrandr --newmode "1440x900_60.00"  106.50  1440 1528 1672 1904  900 903 909 934 -hsync +vsync
xrandr --addmode VGA1 1440x900_60.00
xrandr --output VGA1 --mode 1440x900_60.00

gksudo gedit /usr/bin/lightdmxrandr.sh &

sudo chmod +x /usr/bin/lightdmxrandr.sh

display-setup-script=/usr/bin/lightdmxrandr.sh

gksudo gedit /usr/share/lightdm/lightdm.conf.d/50-ubuntu.conf