The default active cell format in Microsoft Excel isn't all that easy to see, but you can use this easy-to-implement code solution to change that.

To change the cell background with VBA Editor in Excel follow these steps: Launch Microsoft Excel. Click the Developer tab, then click the Visual Basic button. Once the VBA Editor is open, type ...

You can do this using either Excel's ribbon controls or macros. The advantage in using macros is that you can change a cell's value with a single command and then leave it protected afterward.