How can I force a user to fill a certain cell

Hello
I started a validation of an excel sheets, have some questions:
1. how can I force a user to fill a certain cell - say to introduce his name of some form number before he wants to print or before he wants to save? I would not like to use VBA but rather a simple "if" and so on conditions. Could you help with anything particular?

2. Can I leave only a small part of a sheet existing making disappear all the rest? Lets say I need to validate a sheet and I decided to check during the validation every cell in it (not the risk managment approach), can I leave only a part of it an an excell sheet (like a word documents - which contains 1 or 5 or 20 pages - a final number of cells, let's say a rectangle A-G, 1-30