You don't necessarily need Microsoft Excel to work with an .xlsx file Reviewed by Ryan Perian This article explains what XLSX files are, how to open them, and which programs are able to convert ...

How to Convert Read-Only for Excel 2007 to Excel 2003 to Make Changes. When Microsoft rolled out Office 2007, the company made some fundamental changes to its file formats, updating them from ...

Open the spreadsheet in Excel, click "File" and select "Save As." Choose the first "Excel Workbook" option to save the spreadsheet with an .xlsx extension. Convert the OpenOffice.org Calc ...