Sometimes it happens that you received a Microsoft Word 2007 (docx) document and are unable to open it.In Office 2007 Microsoft introduced a new file format called the Microsoft Open Office XML Format (.docx). This format is not compatible with older versions of Microsoft Word.
I am writing about one online service ZamZar, which will help you to convert docx files to doc online. Zamzar also provides other online conversions too. Because the new format is not backwards compatible with previous versions of Microsoft Office you can solve this problem by converting your .docx file to the previous .doc format.
Just browse your file and enter the email id where you want to receive the converted file.