In Office 2007 Microsoft introduced a new file format called the Microsoft Open Office XML Format (.docx).

You can read docx files without having the latest microsoft office istalled. For this you need to have an old office indtalled in your machine.

Now download Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats from microsoft download center. Link here.

Install it. Now right click on docx file==> open with there may be two  Microsoft Office Word, choose one and it does not open correcly choose the other, that will open it correctly.