If you cannot open an Excel file and see Excel cannot open the file because the file format or extension is not valid error, see this post.

If you think that OpenOffice.org is just an open source alternative to Microsoft Office, think again. Find out how it can serve as a component in your Web-based spreadsheet applications.

The Pivot Table is a tool that Excel uses to create custom reports from your spreadsheet databases. All you need is one common, unique field. Here's how to set it up with multiple spreadsheets.

Didn't save your Excel workbook on a Mac? Here are four methods for recovering lost or unsaved Excel files on your Mac.

Microsoft Word can accommodate a surprising number of file formats, and even take in Excel and PowerPoint data, though it might look funny. Here's how.