With the release of Office 2007, Microsoft rolled out a new file format for saving files. The format uses XML to store the data and cannot be opened using the older versions of Office.
There are several instances where people are switching to the newer format, and if you don’t have Office 2007 on your PC you can still open and convert those files to be compatible with your version of office. To open .docx, .xlsx and .pptx files you will have to use any of the methods described below.
Using Office Compatibility Pack
If you have a older version of Microsoft Office, you can still open the new version files using a compatibility pack provided by Microsoft. The compatibility pack is available for download from Microsoft.
Using online Convertors
In the past we have covered several tools to convert files online. Zamzar is the one of the free online convertors, which will allow you to convert .docx, .xlsx and .pptx to a different format. Docx Converter also provides conversion from .docx format to a .doc format.