When a cell
contains formulas that you don't want deleted by accident, use the protection
feature.
1. Press Ctrl + A to select the entire sheet.
2. Choose Format + Cells; in the dialog box that appears, click the
Protection
tab.
3. Deselect Locked and click OK.
4. Choose Edit + Go To.
5. Click Special.
6. Under Select, choose Formulas; then click OK. Excel selects all the cells
that contain formulas.
7. Choose Format + Cells; in the dialog box that appears, click the Protection
tab.
8. Select Locked and click OK.
9. Choose Tools + Protection + Protect Worksheet.
10. In the dialog box that appears, click OK (Passwords can cause more trouble
than they solve).
11. Save the workbook.
If you need to change a formula in the future, choose Tools |
Unprotect, change the cell, and then choose Tools | Protect Worksheet to
protect your formulas again.