1280 by 1024 at 60 hz, most likely the right setting for the monitor, if it is VGA only. If you run lower resolution the picture will be less clear, but have a better frame rate.

You should adjust your graphics settings higher if your FPS is greater than 75, and you should reduce your graphics settings if your FPS is less than 60. Assuming that you have an LCD monitor, it will most likely be able to display only 60-75 FPS (60-75HZ refresh rates). This will allow you to have the highest possible detail without compromising smoothness.

Im not sure about Battlefield 1942, but in Condition Zero you should be able to set the graphics settings to their highest without a problem. Check to see what your refresh rate is (usually 60-75). In the CZ console, use the "fps_max 60" command to make sure that your framerate does not go above what your monitor can display. This will also help smoothen out the gameplay.

Also, if your framerate is still above 75 with the highest graphics settings, try enabling/increasing AA and AF. This will give you a better picture quality.