If you open it from a shortcut, right click on the shortcut (or the icon), choose properties, and choose how to run it: normal, minimized or maximized. Then OK and it should work.
If you open it by clicking on an associated file (such as running Word by clicking on a document, or opening a new window in IE by clicking on a link) it's a different story and, I think, even different for each program involved. Then you'd better tell what programs you mean.
Hope this helps.
When I open a window program, I get a small screen and always have to hit the enlarge to full screen icon. Is there a way to always open the screen to full size?