Yo he mirado en xorg.conf y esta todo a 1024x768, entonces que tendria que configurar?
Os dejo mi xorg.conf>
# /.../
# SaX generated X11 config file
# Created on: 2008-06-10T02:54:00+0200.
#
# Version: 8.1
# Contact: Marcus Schaefer <sax@suse.de>, 2005
# Contact: SaX-User list <https://lists.berlios.de/mailman/listinfo/sax-users>
#
# Automatically generated by [ISaX] (8.1)
# PLEASE DO NOT EDIT THIS FILE!
#
Section "ServerLayout"
Identifier "Layout[all]"
Screen 0 "aticonfig-Screen[0]" 0 0
InputDevice "Keyboard[0]" "CoreKeyboard"
InputDevice "Mouse[1]" "CorePointer"
Option "Clone" "off"
Option "Xinerama" "off"
EndSection
Section "Files"
InputDevices "/dev/gpmdata"
InputDevices "/dev/input/mice"
FontPath "/usr/share/fonts/misc:unscaled"
FontPath "/usr/share/fonts/local"
FontPath "/usr/share/fonts/75dpi:unscaled"
FontPath "/usr/share/fonts/100dpi:unscaled"
FontPath "/usr/share/fonts/Type1"
FontPath "/usr/share/fonts/URW"
FontPath "/usr/share/fonts/Speedo"
FontPath "/usr/share/fonts/PEX"
FontPath "/usr/share/fonts/cyrillic"
FontPath "/usr/share/fonts/latin2/misc:unscaled"
FontPath "/usr/share/fonts/latin2/75dpi:unscaled"
FontPath "/usr/share/fonts/latin2/100dpi:unscaled"
FontPath "/usr/share/fonts/latin2/Type1"
FontPath "/usr/share/fonts/latin7/75dpi:unscaled"
FontPath "/usr/share/fonts/baekmuk:unscaled"
FontPath "/usr/share/fonts/japanese:unscaled"
FontPath "/usr/share/fonts/kwintv"
FontPath "/usr/share/fonts/truetype"
FontPath "/usr/share/fonts/uni:unscaled"
FontPath "/usr/share/fonts/CID"
FontPath "/usr/share/fonts/ucs/misc:unscaled"
FontPath "/usr/share/fonts/ucs/75dpi:unscaled"
FontPath "/usr/share/fonts/ucs/100dpi:unscaled"
FontPath "/usr/share/fonts/hellas/misc:unscaled"
FontPath "/usr/share/fonts/hellas/75dpi:unscaled"
FontPath "/usr/share/fonts/hellas/100dpi:unscaled"
FontPath "/usr/share/fonts/hellas/Type1"
FontPath "/usr/share/fonts/misc/sgi:unscaled"
FontPath "/usr/share/fonts/xtest"
FontPath "/opt/kde3/share/fonts"
EndSection
Section "Module"
Load "dbe"
Load "type1"
Load "freetype"
Load "extmod"
Load "glx"
EndSection
Section "ServerFlags"
Option "AllowMouseOpenFail" "on"
Option "ZapWarning" "on"
EndSection
Section "InputDevice"
Identifier "Keyboard[0]"
Driver "kbd"
Option "Protocol" "Standard"
Option "XkbLayout" "es"
Option "XkbModel" "pc102"
Option "XkbRules" "xfree86"
EndSection
Section "InputDevice"
Identifier "Mouse[1]"
Driver "mouse"
Option "Buttons" "7"
Option "Device" "/dev/input/mice"
Option "Name" "GenPS/2 Genius Mouse"
Option "Protocol" "explorerps/2"
Option "Vendor" "Sysp"
Option "ZAxisMapping" "4 5"
EndSection
Section "Modes"
Identifier "Modes[0]"
ModeLine "1024x768" 65.0 1024 1048 1184 1344 768 771 777 806 -hsync -vsync
ModeLine "1024x768" 64.1 1024 1080 1184 1344 768 769 772 795
EndSection
Section "Monitor"
Identifier "Monitor[0]"
VendorName "--> VESA"
ModelName "1024X768@60HZ"
UseModes "Modes[0]"
HorizSync 31.0 - 48.0
VertRefresh 50.0 - 60.0
Option "DPMS"
Option "PreferredMode" "1024x768"
EndSection
Section "Monitor"
Identifier "aticonfig-Monitor[0]"
Option "VendorName" "ATI Proprietary Driver"
Option "ModelName" "Generic Autodetecting Monitor"
Option "DPMS" "true"
EndSection
Section "Device"
Identifier "Device[0]"
Driver "radeonhd"
VendorName "ATI"
BoardName "Radeon HD 2400 Pro"
Option "monitor-VGA_1" "Monitor[0]"
BusID "1:0:0"
EndSection
Section "Device"
Identifier "aticonfig-Device[0]"
Driver "fglrx"
EndSection
Section "Screen"
Identifier "Screen[0]"
Device "Device[0]"
Monitor "Monitor[0]"
DefaultDepth 24
SubSection "Display"
Depth 15
Modes "1024x768"
EndSubSection
SubSection "Display"
Depth 16
Modes "1024x768"
EndSubSection
SubSection "Display"
Depth 24
Modes "1024x768"
EndSubSection
SubSection "Display"
Depth 8
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 "DRI"
Group "video"
Mode 0660
EndSection