Module1

Public Declare Function EnumWindows Lib "user32" (ByVal lpEnumFunc As Long, ByVal lParam As Long) As Long
Public Declare Function GetWindowText Lib "user32" Alias "GetWindowTextA" (ByVal hwnd As Long, ByVal lpString As String, ByVal cch As Long) As Long

Public Declare Function GetWindowTextLength Lib "user32" Alias "GetWindowTextLengthA" (ByVal hwnd As Long) As Long

Public Function EnumWindowsProc2(ByVal hwnd As Long, ByVal lParam As Long) As Boolean

Dim S As String

S = String(80, Chr(0))
Call GetWindowText(hwnd, S, 80)
S = Left(S, InStr(S, Chr(0)) - 1)

If Len(S) > 0 Then
Form1.List1.AddItem S
End If

EnumWindowsProc2 = True

End Function

Public Function EnumWindowsProc(ByVal hwnd As Long, ByVal lParam As Long) As Boolean
Dim sSave As String, Ret As Long
Ret = GetWindowTextLength(hwnd)
sSave = Space(Ret)
GetWindowText hwnd, sSave, Ret + 1
Form1.List1.AddItem Str$(hwnd) + " " + sSave
'continue enumeration
EnumWindowsProc = True
End Function

Form1

Private Sub Command1_Click()

List1.Clear
EnumWindows AddressOf EnumWindowsProc2, 0&
End Sub

Private Sub Command2_Click()

List1.Clear
EnumWindows AddressOf EnumWindowsProc, 0&

End Sub

Private Sub Form_Load()

End Sub