If you’re using the old version of microsoft office , then you probably have a problem with loading the .docx files . Here is brief tutorial that explains how to convert .docx to .doc files by using free service google docs.
1) Go to docs.google.comand log in your account, if you don’t have accout then create it for free .
2) Click on Upload -> Files…
3) Choose .doc file that you want to convert and click start upload
4) Open .docx file that you want to convert and click on File -> Download as ->Microsoft Word 97 -2003 (.doc)
2nd Method :-
Go to Your file ->right Click to File -> click Properties-> If the Name Of the Given Like :- doument.docx
-> You just Remove the x from .docx and -> Your file now Become -> .doc file