Probelma com resolução de tela Dell Latitude D510

[jedsonic]

Instalei o ubuntu 8.04 numa vmware player e estou tendo dificuldades de alterar a resolução do meu video, a maior resolução disponivel e 800x600 e queria alterar para 1024x768. Ja tentei de tudo e não consigo. segue minha configuração do arquivo xorg.conf

# xorg.conf (X.Org X Window System server configuration file)
#
# This file was generated by failsafeDexconf, using
# values from the debconf database and some overrides to use vesa mode.
#
# You should use dexconf or another such tool for creating a "real" xorg.conf
# For example:
#   sudo dpkg-reconfigure -phigh xserver-xorg
Section "InputDevice"
   Identifier   "Generic Keyboard"
   Driver      "kbd"
   Option      "XkbRules"   "xorg"
   Option      "XkbModel"   "abnt2"
   Option      "XkbLayout"   "br"
   Option      "XkbOptions"   "lv3:ralt_switch"
EndSection

Section "InputDevice"
   Identifier   "Configured Mouse"
   Driver      "vmmouse"
   Option      "Device"   "/dev/input/mice"
EndSection

Section "Device"
   Identifier   "Configured Video Device"
   Boardname   "vesa"
   Busid      "PCI:0:15:0"
   Driver      "vesa"
   Screen   0
EndSection

Section "Monitor"
   Identifier   "Configured Monitor"
   Vendorname   "Plug 'n' Play"
   Modelname   "Plug 'n' Play"
  modeline  "1024x768" 25.2 640 656 752 800 480 490 492 525 -vsync -hsync
   Gamma   1.0
EndSection

Section "Screen"
   Identifier   "Default Screen"
   Device      "Configured Video Device"
   Monitor      "Configured Monitor"
   Defaultdepth   24
   SubSection "Display"
      Depth   24
      Modes      "1024x768"
   EndSubSection
EndSection

Section "ServerLayout"
   Identifier   "Default Layout"
  screen 0 "Default Screen" 0 0
EndSection
Section "Module"
   Load      "glx"
   Load      "GLcore"
   Load      "v4l"
EndSection
Section "ServerFlags"
EndSection

onde sera que estou errando???