Ubuntu- ändra upplösning vid inloggningen?

Hej, har ändrat så att jag har en annan upplösning inne i ubuntu nu.
Men dock så ändrades samtidigt upplösningen som är vid inloggningen till en annan upplösning än det som används när man är inloggad...

Problemet med detta är att en av skärmarna inte klarar av den upplösningen så den bara flimrar.. så jag måste alltså ändra upplösningen som används vid inloggning.. nån som vet hur man gör detta?
Så här ser min config ut:

Section "Files"
FontPath "unix/:7100" # local font server
# if the local font server has problems, we can fall back on these
FontPath "/usr/lib/X11/fonts/misc"
FontPath "/usr/lib/X11/fonts/cyrillic"
FontPath "/usr/lib/X11/fonts/100dpi/:unscaled"
FontPath "/usr/lib/X11/fonts/75dpi/:unscaled"
FontPath "/usr/lib/X11/fonts/Type1"
FontPath "/usr/lib/X11/fonts/CID"
FontPath "/usr/lib/X11/fonts/100dpi"
FontPath "/usr/lib/X11/fonts/75dpi"
# paths to defoma fonts
FontPath "/var/lib/defoma/x-ttcidfont-conf.d/dirs/TrueType"
FontPath "/var/lib/defoma/x-ttcidfont-conf.d/dirs/CID"
EndSection

Section "Module"
Load "bitmap"
Load "dbe"
Load "ddc"
Load "dri"
Load "extmod"
Load "freetype"
Load "glx"
Load "int10"
Load "record"
Load "type1"
Load "vbe"
EndSection

Section "InputDevice"
Identifier "Generic Keyboard"
Driver "keyboard"
Option "CoreKeyboard"
Option "XkbRules" "xorg"
Option "XkbModel" "pc105"
Option "XkbLayout" "se"
EndSection

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

Section "Device"
Identifier "ATI Technologies, Inc. Radeon 9600 XT (RV350 AR)"
Driver "ati"
BusID "PCI:3:0:0"
EndSection

Section "Monitor"
Identifier "DELL D1025HE"
Option "DPMS"
EndSection

Section "Screen"
Identifier "Default Screen"
Device "ATI Technologies, Inc. Radeon 9600 XT (RV350 AR)"
Monitor "DELL D1025HE"
DefaultDepth 24
SubSection "Display"
Depth 1
Modes "1152x864" "1024x768" "800x600" "720x350" "640x480"
EndSubSection
SubSection "Display"
Depth 4
Modes "1152x864" "1024x768" "800x600" "720x350" "640x480"
EndSubSection
SubSection "Display"
Depth 8
Modes "1152x864" "1024x768" "800x600" "720x350" "640x480"
EndSubSection
SubSection "Display"
Depth 15
Modes "1152x864" "1024x768" "800x600" "720x350" "640x480"
EndSubSection
SubSection "Display"
Depth 16
Modes "1152x864" "1024x768" "800x600" "720x350" "640x480"
EndSubSection
SubSection "Display"
Depth 24
Modes "1152x864" "1024x768" "800x600" "720x350" "640x480"
EndSubSection
EndSection

Section "ServerLayout"
Identifier "Default Layout"
Screen "Default Screen"
InputDevice "Generic Keyboard"
InputDevice "Configured Mouse"
EndSection

Section "DRI"
Mode 0666
EndSection