I need to update a workbook periodically and would like to find and
remove old versions of the workbook, on any drive the user has access
to when they open this new file. I just want this code to execute the
first time the workbook is opened by a particular user. I'll be sending
the workbook as an email attachment and have it available on a shared
drive. The workbooks are named similarly; workbookv1, workbookv2, etc.