Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" ( _
            ByVal hWnd1 As Integer, _
            ByVal hWnd2 As Integer, _
            ByVal lpsz1 As String, _
            ByVal lpsz2 As String) _
        As Integer

Δες εδώ http://www.pinvoke.net/default.aspx/user32/FindWindowEx.html

KelMan:

Δες εδώ http://www.pinvoke.net/default.aspx/user32/FindWindowEx.html

manosB:

 
        [DllImport("user32.dll", EntryPoint = "FindWindowExA")]
        private static extern IntPtr FindWindowEx(IntPtr hWnd1, IntPtr hWnd2, string lpsz1, string lpsz2);