Check to see if file is open before opening: VBA Excel

Dim NewWB as workbook
Set NewWb = Workbooks(CStr(Month(Now) & " " & Day(Now) & " " & Year(Now)) & ".xls")

If NewWb Is Nothing Then
  Set NewWb = Workbooks.Add
      With NewWb
          .Title = CStr(DateValue(Now))
          .Subject = "MTB GL Statement"
          .SaveAs Filename:=CStr(Month(Now) & " " & Day(Now) & " " & Year(Now)) & ".xls"
          .SaveAs Filename:=Application.GetSaveAsFilename(fileFilter:="Excel Files (*.xls), *.xls")
      End With
End If