I am having a similar problem. My computer won't open up word documents. It tells me that "This file does not have a program associated with it for performing this action. Please install a program or, if one is already installed, create an association in the Default Programs Control Panel.
The problem is obvious, my computer does not have the .docx extension associated with Word 2010 documents.
I have attempted to find the program for association, but I could not find it. I even checked the link the shortcut I use to open up word points to, but it does not work.
Following Profdlp's suggestion, here is what comes up: