|A couple of questions first:|
Are the users adding data at the end of certain rows or cells, thereby extending the UsedRange of the spreadsheet or are they adding data in a range that is in the middle of other data?
Do you want the cells locked only after the Save operation or do you want the cells locked as soon as the data is entered?
Are you sure that everyone using the spreadsheet will have macros enabled on their systems or at least have the ability to enable them?
It might help if you sent me a copy of the workbook along with an explanation of how and where a user enters data.
I've sent you an email address via Private Message.