If you work with multiple Excel files over the course of a workday, and especially if you use a dual-monitor setup, you might wonder how you can launch each Excel file in its own window so you can ...

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.