must fill up data before user can save file

is it possible to have a user must fill data on some field before he can save? I can't have macro as the environment is protected. If it's possible with formula then it's nice.
Thank you for any help

A formula cannot prevent a user from saving a file. There is no formula that can check if someone tries to save a file. You need VBA to do that, specifically a workbook before change event.

well in that case, is it possible to have any formula show error if certain cells are empty? I want some cells to have filled by user and if left blank then they get some error.... Its not possible na?
Thanks for any help

You can use conditional formatting to highlight cells that must be filled in.
You can also use conditional formatting to display a prominent message if not all mandatory cells have been entered.

See attached for an example. C3 to C10 must have data. If any one of these cells is blank, it will appear with a red fill and cell A1 will display a warning. If all cells have data, no cell is red and A1 shows a friendly reminder to save the file.

your solution sounds right to me. Thanks for the answer. Btw, can you please attach the file in 2003 (.xls) format. My office environment wont use 2007 yet
thanks again

Sorry, I did not pay attention to your Excel version. Here is the file in .xls. I have tested it in 2003 and it works fine.

thank you very much for your help