How to lock cells in Microsoft Excel, so you need a password to change or erase data

You can lock cells in Excel by heading into the program's "Protection" tab. There, you can set a password, and protect your data.
Geeky Gadgets

Master Excel Collaboration with Allow Edit Ranges : Protect and Assign Cell Editing

Have you ever found yourself in a chaotic Excel workbook, where multiple people are editing the same cells, accidentally overwriting each other’s work, or making unintended changes? It’s frustrating, ...
How-To Geek on MSN

Excel's Custom Data Validation: A Trick You Didn't Know You Needed

If you've used data validation in Excel before, you probably selected the relevant cells, clicked "Data Validation" in the ...

How to combine two columns in Excel using formulas, and keep all of their data

You can combine two columns in Excel using several formulas and tools available in the software. Here's how to combine two columns in Excel.