How to Lock Excel 2007 Cells
According to the University of Wisconsin-Eau Claire's LTS Online Help Documentation website, locking the cells in your Excel 2007 document can protect them from accidental changes. The website also notes you must protect the file for the cells to actually lock. Locking individual cells is a simple process.
Click on the cell or cells you want to lock. To lock an individual cell, click on the cell. To lock multiple cells, click on one cell, hold down the left mouse button and drag the box to include the cells you want to lock.
Click "Home" in Excel's top toolbar and click "Format," located in the "Cells" category of the toolbar.
Scroll down in the drop box and click "Lock Cell."
Protect your spreadsheet to complete the process by again clicking "Format" and then "Protect Sheet." Enter a password for your spreadsheet and check the box next to "Select locked cells." Click "OK" and Excel prompts you to reenter your password.