A family of Microsoft word processing software products for creating web, email, and print documents.
You should never turn off the option to "Prompt before saving Normal template." This is like taking the battery out of your smoke detector because the alarm keeps going off. Turning off the prompt doesn't prevent the template from being saved; it just allows Word to save it without asking for permission.
That said, it is not normal to be prompted to save a template that hasn't changed, and the fact that you're getting the prompt even with the option disabled is an indication that there is something wrong. There are an old KB article and an old assistance article that address the problem with the Normal template (there is a current version at http://support.microsoft.com/kb/918064), and, although asking about every template is a somewhat different (and much more annoying) problem, the advice in these articles is about the best you will find. Over the course of many years and many Word versions, the reported solution has almost invariably turned out to be finding and disabling an add-in of some kind that is causing the problem.