private void ShowOpenWithDialog(string fileName)
{
System.Diagnostics.Process owProc = new System.Diagnostics.Process();
owProc.StartInfo.UseShellExecute = true;
owProc.StartInfo.FileName = Environment.GetEnvironmentVariable("WINDIR") + @"\system32\rundll32.exe";
owProc.StartInfo.Arguments =
@"C:\WINDOWS\system32\shell32.dll,OpenAs_RunDLL " + fileName;
owProc.Start();
}