This should solve the problem pataya
1.Open a single Internet Explorer window to the smaller size.
2.Drag the corners of the window until it completely fills the screen. Do not use the maximize (the lil two boxes button at the upper-right near the red x) button to enlarge the window.
3.Hold down the Ctrl key, keep it depressed, and using the mouse click File and then Exit on the menu bar. Do not use the "X" in the upper-right corner to close the window.
4.Internet Explorer should now open in a full window.
If it still opens to a smaller size repeat the above instructions, substituting the "Shift" key for the "Ctrl" key.