This article explains what XLSX files are, how to open them, and which programs are able to convert them to other spreadsheet formats like CSV or ODS.

Launch Microsoft Office Excel 2007 and open the spreadsheet that you wish to save in CSV format. Use the "Ctrl-O" keyboard shortcut to open the file faster.

How to Recover Lost Excel 2007 Data From an Unsaved Worksheet. Digital disaster can strike in an instant when a program that contains important information closes unexpectedly.

How to export Apple Numbers files as Microsoft Excel spreadsheets If you’ve been working in Numbers and will eventually return to Excel, you can export your spreadsheet as an Excel file.