Sure, edit your xorg.conf file with your choice of editor. Under the monitor section it should have your vertical and horizontal refresh rates to your monitor (see the manual to your monitor for that) , then it should have the modlines for the desired resolution and refresh rate. If it doesn't, open a terminal , and type this command.. and then copy the output of that command
(i assume you wanted 768 and not 786...:-P)
once you have copied that output, paste it under the monitor section of xorg.conf , then scroll down to the screen sections, and take out every resolution value except for 1024x768 , once done with that, restart your GUI, and then run kcontrol when back in kde, and i think under the peripherals, monitor section, will have the settings to your resolution and refresh rate, change it to the desired values, and apply changes, and that should be it.
