After my update from 12.04 to 13.10 my display configuration started showing an extra unknown monitor, even though I have nothing connected.

lscpi:

00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)

01:00.0 VGA compatible controller: NVIDIA Corporation GF108M [GeForce GT 540M] (rev a1)

xrandr

Screen 0: minimum 320 x 200, current 1366 x 768, maximum 32767 x 32767

LVDS1 connected primary 1366x768+0+0 (normal left inverted right x axis y axis) 344mm x 194mm

   1366x768       60.0*+   60.1  

   1360x768       59.8     60.0  

   1024x768       60.0  

   800x600        60.3     56.2  

   640x480        59.9  

VGA1 disconnected (normal left inverted right x axis y axis)

HDMI1 disconnected (normal left inverted right x axis y axis)

DP1 disconnected (normal left inverted right x axis y axis)

VIRTUAL1 disconnected (normal left inverted right x axis y axis)

VGA-2 connected (normal left inverted right x axis y axis)

   1024x768       60.0  

   800x600        60.3     56.2  

   848x480        60.0  

   640x480        59.9  

  1024x768 (0x43)   65.0MHz

        h: width  1024 start 1048 end 1184 total 1344 skew    0 clock   48.4KHz

        v: height  768 start  771 end  777 total  806           clock   60.0Hz

  800x600 (0x44)   40.0MHz

        h: width   800 start  840 end  968 total 1056 skew    0 clock   37.9KHz

        v: height  600 start  601 end  605 total  628           clock   60.3Hz

  800x600 (0x45)   36.0MHz

        h: width   800 start  824 end  896 total 1024 skew    0 clock   35.2KHz

        v: height  600 start  601 end  603 total  625           clock   56.2Hz

This problem seems to had been previously asked here and here.

Any ideas on how to solve this?