monitor adjustment

dear /comp/, is there a software to adjust screen width and height?

Play with your monitor's geometry controls at each resolution.  Chances are, if your monitor's controls are digital instead of manual (as in directly controlled by potentiometers), it probably stores custom geometry settings at each resolution & frequency.  Tweaking the geometry at 1600x1200 on such a monitor would not affect the picture at other resolutions.

If that's not it, I'm not sure what your problem is.