Private Sub Button2_Click()
Dim NewRow As Integer
'NewRow = Worksheets("altmain").Range("D7").Value + 1 'your old code
NewRow = Worksheets("table").Range("A65536").End(xlUp).Row + 1 'my solution
If Worksheets("altmain").Range("C6").Value <> 0 Then
MsgBox "There are errors. No data has been added!", vbOKOnly, "MeadInKent"
Exit Sub
End If
Worksheets("table").Cells(NewRow, 1).Value = Worksheets("altmain").Range("B3").Value
Worksheets("table").Cells(NewRow, 2).Value = Worksheets("altmain").Range("B4").Value
Worksheets("table").Cells(NewRow, 3).Value = Worksheets("altmain").Range("B5").Value
MsgBox "New Data added", vbOKOnly, "MeadInKent"
Worksheets("altmain").Range("B3").ClearContents
Worksheets("altmain").Range("D7").Value = NewRow
Worksheets("altmain").Range("B3").Select
End Sub