XLS files are Excel workbook files created in Excel 97 or Excel 2003. The 2007, 2010 and 2013 versions of the program use the XLSX format by default to save workbooks, but can also use the XLS format.

Spreadsheets that contain complicated formulas and a lot of data can take a while to load when you open them in Excel 2007, but that's not the only reason spreadsheets can be slow to load. Microsoft ...

If you notice that your Excel files are opening in Notepad, then read this post to learn how to fix the issue. The default behavior of a document or file is to open in the application with which it ...

With the introduction of Office 2007, Microsoft abandoned the age-old .doc format in favor of the newer .docx (also known as the Office Open XML format). If you’re still using Word 2003 or an earlier ...