Word 2010 running multiple instances

[JBE]

I often get this error when closing a document: This file is in use by another application or user ...Normal.dotm. The reason, I believe, this error shows up is because more than one instance (sometimes 3 or more) of WinWord.exe are running in the event viewer. So when I close out one document, Word tries to update the default template, but it is locked on the other instance, hence the error. So my question here is how do I determine what is causing Word to start more than one instance and how do I fix and prevent it. I have tried deleting normal.dotm, which did not help.