By default all cells in a worksheet are locked (see image below). I.e when you protect a worksheet every cell in the worksheet will be protected.

To handle cell protection differently then you have change the default settings for the required cells.
Here is a scenario to protect formula cells but allow access to data cells:
- Select all cells in the worksheet by clicking on the top left corner of the sheet.
- On the Format menu Click Cells.
- Click on the Protection tab.
- Uncheck the Locked and Hidden check boxes, then click OK.
These four steps will make all cells in the worksheet unprotected and can therefor be modified. Next step is to protect the formula cells, and here is how we do it:
- Select all cells that have formulas.
- On the Format menu Click Cells.
- Click on the Protection tab.
- Check the Locked and Hidden check boxes, then click OK.
- On the Tools menu click Protection and select Protect sheet.
Applies to: Excel 2003