If you successfully installed the drivers then did you enable the ATI restricted drivers (System>Administration>Restricted Drivers Manager)?
Here is my xorg.conf:
Section "ServerLayout"
# Uncomment if you have a wacom tablet
# InputDevice "stylus" "SendCoreEvents"
# InputDevice "cursor" "SendCoreEvents"
# InputDevice "eraser" "SendCoreEvents"
Identifier "Default Layout"
screen 0 "aticonfig-Screen[0]" 0 0
Inputdevice "Generic Keyboard"
Inputdevice "Configured Mouse"
EndSection
Section "Files"
EndSection
Section "Module"
Load "glx"
EndSection
Section "InputDevice"
Identifier "Generic Keyboard"
Driver "kbd"
Option "CoreKeyboard"
Option "XkbRules" "xorg"
Option "XkbModel" "pc101"
Option "XkbLayout" "us"
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"
Identifier "stylus"
Driver "wacom"
Option "Device" "/dev/input/wacom"
Option "Type" "stylus"
Option "ForceDevice" "ISDV4"# Tablet PC ONLY
EndSection
Section "InputDevice"
Identifier "eraser"
Driver "wacom"
Option "Device" "/dev/input/wacom"
Option "Type" "eraser"
Option "ForceDevice" "ISDV4"# Tablet PC ONLY
EndSection
Section "InputDevice"
Identifier "cursor"
Driver "wacom"
Option "Device" "/dev/input/wacom"
Option "Type" "cursor"
Option "ForceDevice" "ISDV4"# Tablet PC ONLY
EndSection
Section "Monitor"
Identifier "Generic Monitor"
Horizsync 28.0 - 51.0
Vertrefresh 43.0 - 60.0
Option "DPMS"
EndSection
Section "Monitor"
Identifier "aticonfig-Monitor[0]"
Option "VendorName" "ATI Proprietary Driver"
Option "ModelName" "Generic Autodetecting Monitor"
Option "DPMS" "true"
EndSection
Section "Device"
Identifier "Generic Video Card"
Driver "fglrx"
Busid "PCI:5:0:0"
EndSection
Section "Device"
Identifier "aticonfig-Device[0]"
Driver "fglrx"
Option "VideoOverlay" "on"
Option "OpenGLOverlay" "off"
EndSection
Section "Screen"
Identifier "Default Screen"
Device "Generic Video Card"
Monitor "Generic Monitor"
Defaultdepth 24
SubSection "Display"
Modes "1024x768"
EndSubSection
EndSection
Section "Screen"
Identifier "aticonfig-Screen[0]"
Device "aticonfig-Device[0]"
Monitor "aticonfig-Monitor[0]"
Defaultdepth 24
SubSection "Display"
Viewport 0 0
Depth 24
EndSubSection
EndSection
Section "Extensions"
Option "Composite" "1"
EndSection
Section "ServerFlags"
Option "AIGLX" "on"
EndSection
I hope this helps.



