How to Open Excel 2007 Files As Separate Windows. 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 ...

These free add-ins for Word, Excel, and PowerPoint enable those apps to open and save their ODF counterparts (which typically have .ODT, .ODS, and .ODP extensions, respectively).

I also tested the plugin with a highly complex ODS file. In Excel, users load ODS files by clicking a special button in a toolbar rather than using the regular Open operation from the File menu.