It happened to me several times that I sent a Word file any new or old version (2003 , 2010 , for example) the program that I have, then I can not open these files. But luckily there is a way to convert files Docx to Doc that solve such problems .
It is easy to use you just have to DOCX upload and select the format. Doc. Then the system will make the changes to the file, and give you a link where you download format Doc.
Nothing easier than convert Docx to Doc with this application online. Also no record calls and is completely free.
Link: Official Website