Locking a column in Excel is a great way to protect your data. You can do this by selecting the column you want to lock, right-clicking to open the context menu, and then choosing 'Format Cells.' In the 'Protection' tab, ensure 'Locked' is checked. Finally, go to 'Review' and select 'Protect Sheet,' setting a password if you wish. What kind of data are you looking to protect in Excel? Do you often work with sensitive information in your spreadsheets?