Ubuntu: No screens found - What's wrong with this xorg?

Question

due to problems with flickering und rough edges on windows, even without nvidia drivers, I try to rebuild the whole xorg by hand. I ran X -configure and got a standard xorg.conf I have to edit. I set my monitor but always get a "No screens found". How does that come?
Here is my current xorg.conf

Section "ServerLayout"
 Identifier     "X.org Configured"
 Screen         0 "Screen0" 0 0
 InputDevice    "Mouse0" "CorePointer"
 InputDevice    "Keyboard0" "CoreKeyboard"
EndSection

Section "Files"
 ModulePath   "/usr/lib/xorg/modules"
 FontPath     "/usr/share/fonts/X11/misc"
 FontPath     "/usr/share/fonts/X11/cyrillic"
 FontPath     "/usr/share/fonts/X11/100dpi/:unscaled"
 FontPath     "/usr/share/fonts/X11/75dpi/:unscaled"
 FontPath     "/usr/share/fonts/X11/Type1"
 FontPath     "/usr/share/fonts/X11/100dpi"
 FontPath     "/usr/share/fonts/X11/75dpi"
 FontPath     "/var/lib/defoma/x-ttcidfont-conf.d/dirs/TrueType"
 FontPath     "built-ins"
EndSection

Section "Module"
 Load  "glx"
 Load  "dbe"
 Load  "record"
 Load  "dri2"
 Load  "dri"
 Load  "extmod"
EndSection

Section "InputDevice"
 Identifier  "Keyboard0"
 Driver      "kbd"
EndSection

Section "InputDevice"
 Identifier  "Mouse0"
 Driver      "mouse"
 Option     "Protocol" "auto"
 Option     "Device" "/dev/input/mice"
 Option     "ZAxisMapping" "4 5 6 7"
EndSection

Section "Monitor"
 Identifier   "SamsungSyncMasterP2770"
 HorizSync    30-75
 VertRefresh  56-61
 Modeline "1920x1080@60" 182.28 1920 1952 2640 2672 1080 1102 1113 1135
EndSection

Section "Device"
        ### Available Driver options are:-
        ### Values: <i>: integer, <f>: float, <bool>: "True"/"False",
        ### <string>: "String", <freq>: "<f> Hz/kHz/MHz",
        ### <percent>: "<f>%"
        ### [arg]: arg optional
        #Option     "SWcursor"            # [<bool>]
        #Option     "HWcursor"            # [<bool>]
        #Option     "NoAccel"             # [<bool>]
        #Option     "ShadowFB"            # [<bool>]
        #Option     "UseFBDev"            # [<bool>]
        #Option     "Rotate"              # [<str>]
        #Option     "VideoKey"            # <i>
        #Option     "FlatPanel"           # [<bool>]
        #Option     "FPDither"            # [<bool>]
        #Option     "CrtcNumber"          # <i>
        #Option     "FPScale"             # [<bool>]
        #Option     "FPTweak"             # <i>
        #Option     "DualHead"            # [<bool>]
 Identifier  "Card0"
 Driver      "nv"
 BusID       "PCI:1:0:0"
EndSection

Section "Screen"
 Identifier "Screen0"
 Device     "Card0"
 Monitor    "SamsungSyncMasterP2770"
 DefaultDepth 24
 SubSection "Display"
  Viewport   0 0
  Depth     1
 EndSubSection
 SubSection "Display"
  Viewport   0 0
  Depth     4
 EndSubSection
 SubSection "Display"
  Viewport   0 0
  Depth     8
 EndSubSection
 SubSection "Display"
  Viewport   0 0
  Depth     15
 EndSubSection
 SubSection "Display"
  Viewport   0 0
  Depth     16
 EndSubSection
 SubSection "Display"
  Viewport   0 0
  Depth     24
  Modes  "1920x1080@60"
 EndSubSection
EndSection

By the way. Why is there no xorg.conf by default? How does Ubuntu get any graphical data without it?

Here is the xorg output (It's 2 because I test the configuration with xinit -- :2)

[  7441.101] 
X.Org X Server 1.9.0
Release Date: 2010-08-20
[  7441.101] X Protocol Version 11, Revision 0
[  7441.101] Build Operating System: Linux 2.6.24-27-server x86_

Solution

[ 7441.884] (EE) NV: Kernel modesetting driver in use, refusing to load

Pass nomodeset on the kernel command line in the bootloader.