I'm trying to create a excel macro calculating a sum of values in column A, using a certain dynamic range.
Basic excel example screenshot included below:

The final goal is to loop through the cells in column B till a "0" is reached. When a "0" is reached, in column A of that same row, a sum of all the values in column A is calculated until a new "0" in column B is reached. So in this basic example A1 should contain =sum(A2:A7) and A8 should contain the sum of the values A9 through A14.
My progress so far included below, still pretty new at all the VBA stuff.
Sub sumtill0()
'
' sumtill0 Macro
'
'
Cells(ActiveCell.Row, 1).Select
If Sheets("Blad1").Cells(2, 1).Value = nil And Sheets("Blad1").Cells(2, 1).Value <> "0" Then
Sheets("Blad1").Activate
Cells(2, 1).Range("A1").Select
Else
Dim artTekst As String
If Sheets("Blad1").Cells(1, 2).Value = "0" Then
Sheets("Blad1").Cells(1, 1).Fomula = "=SUM()"
Else
If Sheets("Blad1").Cells(1, 2).End(xlDown).Value = "0" Then
Sheets("Blad1").Cells(1, 1).End(xlDown).Offset(1, 0).Value = "0"
Sheets("Blad1").Cells(1, 1).End(xlDown).Fomula = "=SUM(???)"
ActiveCell.Value = Sheets("Blad1").Cells(1, 2).End(xlDown).Offset(0, -2).Value
End If
End If
End If
End Sub
Thanks :)