effetti desktop ati 9550

[poi]

Qualcuno abbia pietà di me!
Ho installato Ubunto 7.0.4 e,cercando di abilitare gli effetti desktop mi appare una schermata bianca.
Ho cercato in tutti i post,le ho provate tutte ma non funziona.
Allego fiducioso il file xorg

# /etc/X11/xorg.conf (xorg X Window System server configuration file)
#
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
#
# Edit this file with caution, and see the xorg.conf(5) manual page.
# (Type "man xorg.conf" at the shell prompt.)
#
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# package.
#
# If you have edited this file but would like it to be automatically updated
# again, run the following command:
#  sudo dpkg-reconfigure -phigh xserver-xorg

Section "Files"
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"
# path to defoma fonts
FontPath "/var/lib/defoma/x-ttcidfont-conf.d/dirs/TrueType"
EndSection

Section "Module"
Load "bitmap"
Load "ddc"
Load "dri"
Load "extmod"
Load "freetype"
Load "glx"
Load "int10"
Load "vbe"
EndSection

Section "InputDevice"
Identifier "Generic Keyboard"
Driver "kbd"
Option "CoreKeyboard"
Option "XkbRules" "xorg"
Option "XkbModel" "pc105"
Option "XkbLayout" "it"
EndSection

Section "InputDevice"
Identifier "Configured Mouse"
Driver "mouse"
Option "CorePointer"
Option "Device" "/dev/input/mice"
Option "Protocol" "ImPS/2"
Option "ZAxisMapping" "4 5"
Option "Emulate3Buttons" "true"
EndSection

Section "InputDevice"
Driver "wacom"
Identifier "stylus"
Option "Device" "/dev/input/wacom"
Option "Type" "stylus"
Option "ForceDevice" "ISDV4" # Tablet PC ONLY
EndSection

Section "InputDevice"
Driver "wacom"
Identifier "eraser"
Option "Device" "/dev/input/wacom"
Option "Type" "eraser"
Option "ForceDevice" "ISDV4" # Tablet PC ONLY
EndSection

Section "InputDevice"
Driver "wacom"
Identifier "cursor"
Option "Device" "/dev/input/wacom"
Option "Type" "cursor"
Option "ForceDevice" "ISDV4" # Tablet PC ONLY
EndSection

Section "Device"
Identifier "ATI Radeon 9550"
Driver "fglrx"
BusID "PCI:1:0:0"
VideoRam 256000
EndSection

Section "Extensions"
Option "Composite" "0"
EndSection

Section "Monitor"
Identifier "Monitor Generico"
Option "DPMS"
HorizSync 30-65
VertRefresh 50-75
EndSection

Section "Screen"
Identifier "Default Screen"
Device "ATI Radeon 9550"
Monitor "Monitor Generico"
DefaultDepth 24
SubSection "Display"
Depth 1
Modes "1280x1024" "1280x960" "1280x854" "1280x800" "1280x768" "1200x800" "1152x864" "1152x768" "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 4
Modes "1280x1024" "1280x960" "1280x854" "1280x800" "1280x768" "1200x800" "1152x864" "1152x768" "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 8
Modes "1280x1024" "1280x960" "1280x854" "1280x800" "1280x768" "1200x800" "1152x864" "1152x768" "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 15
Modes "1280x1024" "1280x960" "1280x854" "1280x800" "1280x768" "1200x800" "1152x864" "1152x768" "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 16
Modes "1280x1024" "1280x960" "1280x854" "1280x800" "1280x768" "1200x800" "1152x864" "1152x768" "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 24
Modes "1280x1024" "1280x960" "1280x854" "1280x800" "1280x768" "1200x800" "1152x864" "1152x768" "1024x768" "800x600" "640x480"
EndSubSection
EndSection

Section "ServerLayout"
Identifier "Default Layout"
Screen "Default Screen"
InputDevice "Generic Keyboard"
InputDevice "Configured Mouse"
InputDevice    "stylus" "SendCoreEvents"
InputDevice    "cursor" "SendCoreEvents"
InputDevice    "eraser" "SendCoreEvents"
EndSection

Section "Extensions"
  Option "Composite" "Enable"
EndSection

Section "DRI"
Mode 0666
EndSection

Grazie