How to: Protect a cell in a worksheet.
Solution:
Select the cell and select 'Cells...' from the 'Format' menu.
1) Select the cell to protect.
2) Select the 'Format' menu and select 'Cells...'. (The Format Cells dialog box appears.)
3) Click the 'Protection' tab.
4) Do one or both of the following:
a) Select the 'Locked' check box to prevent changes to the selected cell.
b) Select the 'Hidden' check box so that if the cell contains a formula, the formula will not appear in the formula bar when the cell is selected.
NOTE: The worksheet must be protected before the cell protection takes effect.
5) Click 'OK'.