The X Factor - File Changes introduced in Microsoft Office 2007 and Preserved Henceforth

MS Office 2007 introduced new file extensions - XLSX for Excel, PPTX for Powerpoint and DOCX for Word. These are generally smaller in size than their pre-Office 2007 equivalents. These use Office XML. So, for example, a PPTX file would an XML-based Powerpoint presentation. Note that these file formats disallow macros. The corresponding macro-enabled versions all have the X replaced with an M - hence we have XLSM for a macro-enabled Excel workbook, PPTM for a macro-enabled Powerpoint presentation and DOCM for a macro-enable Word document. In theory, these XML formats allow the files to be consumed by a variety of applications, not just Word, Excel or Powerpoint and allow batch processing software to be built, for example processing automatically hundreds of Word documents.

Where are the Heading 2, Heading 3 et. cetera styles in Word and why are they not showing up?

To make these show up, you need to click on the bottom right of the Styles tab. This brings up a floating menu.

At the bottom of the floating menu are three icons representing: New Style, Style Inspector and Manage Styles. Click on Manage Styles.

Click on the second tab (Recommend). Select what you would like to see and click Show. This will make the style show up when viewing recommended styles.