screen size incorrect

[LunaticHiatus]

I am having issue controlling the width and heigtht of my monitor. Kubuntu is under the impression that it is larger then what it is. Everything displays fine but it cuts off the taskbar and moves it too far to the right.
Changing the resolution does nothing.

[abrianb]

Is there any chance that you have two cables running from your graphics card to your monitor? If you do, then remove one cable and reboot. I had two cables for years without problems, recently my system acted as you are describing. Hope this helps.