Dim a&, b&, c&, d&, Max%, X&(9), Feld&(9)
 
Max = UBound(Feld)
For a = 1 To Max
  X(0) = a
  For b = 2 To Max
    X(1) = b
    For c = 3 To Max
      X(2) = c
      For d = 4 To Max
        X(3) = d
        'usw.
        '...
      Next d
    Next c
  Next b
Next a

Private Sub Form_Activate()
 
Dim X&(), Max%, Summe$, i%, S%, FlgEnd As Boolean
 
S = 7 'Zahl der Schleifen
Max = 9 'Obergrenze
ReDim X(S)
For i = 1 To S
  X(i) = i 'Startwerte setzen
Next i
FlgEnd = False
Do
  'Zugriff auf Schleifenwerte:
  Summe = ""
  For i = 1 To S
    Summe = X(i) & " " & Summe
  Next i
  Me.Caption = Summe
  'Nächsten Wert ermitteln
  For i = 1 To S
    X(i) = X(i) + 1 'erhöhen
    If X(i) <= Max Then
      Exit For
    ElseIf i = S Then
      FlgEnd = True 'Fertig, alle durch
      Exit For
    End If
    X(i) = i 'zurücksetzen
  Next i
  DoEvents
Loop While FlgEnd = False
 
End Sub