We are using DNN 7.2.2 to develop a new Intranet site for our Company which will only be usable from a computer on our network.  We are having an issue with Word and Excel documents which are uploaded to the site and then linked to a hyperlink to allow users to download and view the documents.  We are for the majority using PDF on our website but there are a few instances where we need to use word or excel documents.  The issue we are having is that it asks for a user name and password in a popup window.  How do I stop this from happening with out requiring every user to register for the intranet site?  We are not making user names and passwords for all users because there is nothing sensitive being stored on the website and there is no need for restrictions on the site.  

If you need more information in order to be able to help me please let me know and thank you in advance for any help.