Create a Module with
Sub Auto_Open()
'initialize Cells A1 thru A15 to blank
Sheets("Sheet1").Range("A1:A15").Value = ""
'initialize Cells B1 thru B15 to zero(0)
Sheets("Sheet1").Range("B1:B15").Value = 0
'initialize Cells A20 thru B40 to blank
Sheets("Sheet1").Range("A20:B40").Value = ""
'initialize Cells C20 thru D40 to zero(0)
Sheets("Sheet1").Range("C20:D40").Value = 0
End Sub