Powershell list untitled windows' process names (modified version of http://powershell-knowhow.de/powershell/?p=321)

listwin.ps1

$TypeDef = @"

using System;
using System.Text;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Diagnostics;

namespace Api
{

 public class WinStruct
 {
   public string WinTitle {get; set; }
   public int WinHwnd { get; set; }
   public string ProcName { get; set; }
   public bool Visible { get; set; }
 }

 public class ApiDef
 {
   private delegate bool CallBackPtr(int hwnd, int lParam);
   private static CallBackPtr callBackPtr = Callback;
   private static List<WinStruct> _WinStructList = new List<WinStruct>();

   [DllImport("User32.dll")]
   [return: MarshalAs(UnmanagedType.Bool)]
   private static extern bool EnumWindows(CallBackPtr lpEnumFunc, IntPtr lParam);

   [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
   static extern int GetWindowText(IntPtr hWnd, StringBuilder lpString, int nMaxCount);
   
   [DllImport("user32.dll", SetLastError=true)]
   static extern uint GetWindowThreadProcessId(IntPtr hWnd, out uint processId);

   [DllImport("user32.dll")]
   [return: MarshalAs(UnmanagedType.Bool)]
   static extern bool IsWindowVisible(IntPtr hWnd);

   private static bool Callback(int hWnd, int lparam)
   {
       StringBuilder sb = new StringBuilder(256);
       int res = GetWindowText((IntPtr)hWnd, sb, 256);
       try {
           uint pid;
           GetWindowThreadProcessId((IntPtr)hWnd, out pid);
           Process p = Process.GetProcessById((int)pid);
           _WinStructList.Add(new WinStruct { WinHwnd = hWnd, WinTitle = sb.ToString(), ProcName = p.Modules[0].FileName, Visible = IsWindowVisible((IntPtr)hWnd) });
           return true;
       } catch {}
       _WinStructList.Add(new WinStruct { WinHwnd = hWnd, WinTitle = sb.ToString() });
       return true;
   }   

   public static List<WinStruct> GetWindows()
   {
      _WinStructList.Clear();
      EnumWindows(callBackPtr, IntPtr.Zero);
      return _WinStructList;
   }

 }
}
"@

Add-Type -TypeDefinition $TypeDef -Language CSharpVersion3

[Api.Apidef]::GetWindows() | Where-Object { $_.WinTitle -eq "" -and $_.Visible } | Sort-Object -Property ProcName | Select-Object ProcName