All Window appears in full screen mode

using System.Runtime.InteropServices;

[StructLayout(LayoutKind.Sequential)]
public struct RECT
{
    public int Left;
    public int Top;
    public int Right;
    public int Bottom;
}

public bool IsFullScreen()
{
    bool runningFullScreen = false;
    RECT appBounds;
    Rectangle screenBounds;
    IntPtr hWnd;

    //get the dimensions of the active window
    hWnd = GetForegroundWindow();
    if (hWnd!=null && !hWnd.Equals(IntPtr.Zero))
    {
        //Check we haven't picked up the desktop or the shell
        if (!(hWnd.Equals(desktopHandle) || hWnd.Equals(shellHandle)))
        {
            GetWindowRect(hWnd, out appBounds);
            //determine if window is fullscreen
            screenBounds = Screen.FromHandle(hWnd).Bounds;
            if ((appBounds.Bottom - appBounds.Top) == screenBounds.Height && (appBounds.Right - appBounds.Left) == screenBounds.Width)
            {
                runningFullScreen = true;
            }
        }
    }
    return runningFullScreen;
}

public void SetNormal()
{
    IntPtr hWnd;
    Rectangle screenBounds;

    //get the dimensions of the active window
    hWnd = GetForegroundWindow();
    screenBounds = Screen.FromHandle(hWnd).Bounds;
    screenBounds.Height -= 50;
    screenBounds.Width  -= 250;

}