excel Protecting formulas from being overwritten

In many cases, you might want to protect your formulas from being overwritten or modified. To
do so, perform the following steps:
1. Select the cells that may be overwritten.
2. Right-click and choose Format Cells from the shortcut menu.
3. In the Format Cells dialog box, click the Protection tab.
4. In the Protection tab, clear the Locked check box.
5. Click OK to close the Format Cells dialog box.
6. Choose Review➜Changes➜Protect Sheet to display the Protect Sheet dialog box, as
shown in Figure 2-18.
7. In the Protect Sheet dialog box, select the options that correspond to the actions to
allow, specify a password if desired, and then click OK.