EDIT THE /etc/X11/XF86Config file:
Open up the console and type:
"kdesu kedit /etc/X11/XF86Config"
You are prompted to insert the root password. Insert it and the file will
opened as root.
Under the "Monitor" section of the file set your monitor's specific horizontal
and vertical refresh rates replacing the existing values with the correct values for your monitor.
If you dont know the values search in your monitor's manual, manefacturer's site or simply google.
#CAUTION# You must set these values correctly because incorrect values can damage your monitor!!!!
To add more resolution modes or increase your default resolution:
Under the "Screen" after the word "modes" simply add modes. The first mode should me the highest resolution and the last the lower.
"1280x1024" "1152x864" "1152x768" "1024x768"
Now save the file, exit and reboot.