Foolproof fix for screen resolution?

[Burgoo King]

Greetings and thanks in advance for assistance.

In a nutshell, what is the easiest and most foolproof way for me to 
change my screen resolution from 1680x1050 to a more readable 1280x768?  
The resolution that I want is not offered as a choice in the drop-down 
list under System>Preferences>Screen Resolution.


I've installed hardy-heron which seems to work well except for the 
screen resolution.

My home-made desktop computer has an Intel 82865G (i810) graphics 
adapter on the motherboard.  The monitor is a Samsung SyncMaster 204BW 
20" flat-screen TFT-LCD monitor.

My preferred screen resolution is available under MS Windows after 
installing Samsung software.  Using the MS Windows program PowerStrip, I 
obtained the following ModeLine which is supposed to help in migrating 
to Linux.

"1280x768" 80.250 1280 1344 1480 1680 768 769 772 795 -hsync +vsync

I tried pasting that line into the xorg.conf file in another version of 
Linux but had unsatisfactory results -- the resolution was right, but I 
never saw the task bar again.

Also from PowerStrip, there is this info which is not very meaningful to me.

- PowerStrip timing parameters:
      1280x768=1280,64,136,200,768,1,3,23,80250,514
 
- Generic timing details for 1280x768:
      HFP=64 HSW=136 HBP=200 kHz=48 VFP=1 VSW=3 VBP=23 Hz=60

- VESA detailed timing:
      PClk=80.25 H.Active=1280 H.Blank=400 H.Offset=48 HSW=136 
V.Active=768 V.Blank=27 V.Offset=1 VSW=3

Lastly, following is the content of the current etc\X11\xorg.conf file.  
It seems to be short on details about the monitor and screen.  I'll 
appreciate a tip on how to proceed from here with minimum risk of 
fouling up the otherwise nice configuration.

-- Charles Rathbone


# xorg.conf (X.Org 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 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 "InputDevice"
    Identifier    "Generic Keyboard"
    Driver        "kbd"
    Option        "XkbRules"    "xorg"
    Option        "XkbModel"    "pc105"
    Option        "XkbLayout"    "us"
EndSection

Section "InputDevice"
    Identifier    "Configured Mouse"
    Driver        "mouse"
    Option        "CorePointer"
EndSection

Section "Device"
    Identifier    "Configured Video Device"
EndSection

Section "Monitor"
    Identifier    "Configured Monitor"
EndSection

Section "Screen"
    Identifier    "Default Screen"
    Monitor        "Configured Monitor"
    Device        "Configured Video Device"
EndSection

Section "ServerLayout"
    Identifier    "Default Layout"
    Screen        "Default Screen"
EndSection

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