Desktop resolution

hi all! i have a problem with desktop resolution. my screen resolution is 1600x900 and by default the computer auto select 1280x1024. this is not suitable with my monitor, and cause me can’t see the task bar at the bottom of screen. when i go KRandRTray to change the resolution, there are not the suitable screen resolution to my monitor. It only hv 1280x1024, 1280x960, 1024x768,800x600,…
how can i change it to 1440x900 or 1xxx by 900?

Do you have installed any video drivers?
Have you tried to configure it with Sax2?