Macro Security Warning in a Word document even when there are no macros

I was getting Macro Security Warning in a word document everytime I opened it, and there was no macros in the document. After doing some investigation, here is what I found:

The Macro Security Warning can be because of two reasons:

1. Third party components are interfering with MS Word. In this case you should get macro security warning in each of the word document. Try uninstalling some applications which provide add-in support to MS Word like "Microsoft office live add-in" or any add-in which supports printing to PDF.

2. Macros were added and removed from the document. It has been explained here with solutions - http://support.microsoft.com/kb/290960 .

I used a variation of Method 3 explained in the KB article mentioned in option 2 above. I saved the ".doc" file in ".docx" format, and the security warning is gone. I again saved ".docx" back to ".doc" and there is no more security warning.