auto save when open and adding current date to file

I am trying to idiot proof my workbook to auto save upon opening with the same file name with the current date added on the end. I have the file write protected by selecting properties and checking the box to write protect.

I do not see a new file name being created.

Private Sub Workbook_Open()
    objWorkbook.SaveAs "K:\Test\" & objWorkbook.Name & Format(Date, "MMMddYYYY")
End Sub

Thanks in Advance,

Christopher aka Ferrum