Hi Bob
Choose Tools>Protection>Protect Sheet - you can use a password or leave it
blank. (If you do use a password, write it down to remember it!!).
Protecting a sheet mean cells which are locked cannot be overwritten.
Cells are Locked as the Default setting.
Before you protect the sheet, select the cells which you require the user to
enter data and Format>Cells>Protection and remove the tick from Locked.
Passwords in Excel are not totally secure. They will deter the in
experienced user, but there are plenty of readily available password
crackers available for those who wish to break them.
Regards
Roger Govier