I'd start from looking at one of the examples on the inet, like this:

http://www.codeproject.com/csharp/popupkiller.asp

It shows working with different windows ona popup killer example.

Andrey

I've got a class that seems to do the trick.  I started with Taylor
Wood's class, here:

<http://www.thecodeproject.com/csharp/windowhider.asp>

and pared it down to just what I wanted; it seems to be working fine.
Enjoy.

using System;
using System.Runtime.InteropServices;
using System.Collections;
using System.Windows.Forms;

namespace Whatever
{
/// <summary>
/// Collection of Forms visible in this application,
/// in current z-order (front to back)
/// </summary>
/// <example>
///    foreach (Form form in new WindowList())
///        {
///        // process forms as needed
///        }
/// </example>

public class WindowList : IEnumerable, IEnumerator
{
[DllImport("user32.dll")]
private static extern int EnumWindows(ewProc ewp, int lParam);

public delegate bool ewProc(int hWnd, int lParam);

private int currentIndex = -1;
private ArrayList windows = new ArrayList();

public WindowList()
{
EnumWindows(new ewProc(AddWindow), 0);
}

private bool AddWindow(int hWnd, int lParam)
{
Control form = Form.FromHandle((IntPtr)hWnd);
if (form != null && form.Visible)
windows.Add(form);
return true;
}

public IEnumerator GetEnumerator()
{
return (IEnumerator)this;
}
public bool MoveNext()
{
currentIndex++;
return currentIndex < windows.Count;
}
public void Reset()
{
currentIndex = -1;
}
public object Current
{
            get
                {
                return windows[currentIndex];
                }
            }
        }
    }