If I'm understanding this correctly, you want to select the cells from
startinf from A1 that have data? If so, try this:

Sub Macro8()

With Sheets("Sheet1")
.Range(.Range("A1"), .Range("A1").End(xlDown)).Select
End With

End Sub

I think part of the issue is that you need to use a fully qualified
reference for the range. Hopefully this works or at least helps.