Good Morning Don,
Usually when a document number increases by one, you are using a template file rather than a document file? If the file type has yellow at the top of the icon then this is a template file. Open the document, click on file save as, but at the bottom change the file type to 'Word Document'.
I'm sure you're aware of the above, therefore it must be a driver fault which is a little more difficult to track down. When using safe mode it limits the amount of drivers that word will use. Have you recently installed a new program? It may be that this driver is affecting the way that Microsoft Word works?
To stop drivers from loading, you will have to stop and start several to find out which one is causing the problem, try the following information…
http://www.microsoft.com/resources/d....mspx?mfr=true
Hope this helps.