Probleme mit Worksheet Change

Private Sub Worksheet_Change(ByVal Target As Excel.Range)

If ActiveCell.Column <> 3 Then Exit Sub
If Target.Cells.Count > 1 Then Exit Sub
For x = 1 To 2000
    Zeile = Cells(x, 1)
    If Zeile = "" Then  
        Exit For
    End If
Next
            If Cells(x, 3).Value < 0 Then
                Step = 1
            ElseIf Cells(x, 3).Value > 0 Then
                Step = 2
            ElseIf Cells(x, 3).Value = 0 Then
                Step = 3
            End If
            Select Case Step
            Case 1
                Cells(x, 3).NumberFormat = "#,##0.00 $"  
                Cells(x, 3).Interior.Color = 13551615
                Cells(x, 3).Font.Color = 255
                Cells(x, 4) = Cells(x, 3) + Cells(x - 1, 4) 'Hier kommt dann immer der Fehler und er beginnt den Code wieder von vorne zu bearbeiten  
                Cells(x, 4).NumberFormat = "#,##0.00 $"  
                Cells(x, 4).Interior.Color = 13551615
                Cells(x, 4).Font.Color = 192
            Case 2
                Cells(x, 3).NumberFormat = "#,##0.00 $"  
                Cells(x, 3).Interior.Color = 13561798
                Cells(x, 3).Font.Color = 24832
                Cells(x, 4) = Cells(x, 3) + Cells(x - 1, 4)
                Cells(x, 4).NumberFormat = "#,##0.00 $"  
                Cells(x, 4).Interior.Color = 13561798
                Cells(x, 4).Font.Color = 24832
            Case 3
                Cells(x, 3).NumberFormat = "#,##0.00 $"  
            Case Else
        End Select
End Sub