FBA Users, Open Files in Client's Program/Tools

I have an (extended web application from default web application using windows authentication) internet facing site using FBA and experiencing a weird issue when trying to open (uploaded word and excel documents or video files or any other file which needs client program to show/run/display) it does not work.

Following are the different behaviour for different files

Word Document: Microsoft Word Application run but does not display any document
Excel Document:
.WMV File:

After searching on the internet I found the following forum which helped me:

Assume your client is a vista machine. If you run your IE in protected mode (normally it is), then you need to add your server as trusted location. Otherwise you need to run your IE in administrative mode. (right click "run as administrator")
Then when you login in IE you need to check "Sign me in automatically", which will persist your credential.

http://social.technet.microsoft.com/Forums/en-US/sharepointgeneral/thread/0811935c-c69a-4eb4-b319-63cc139ac727

In order to enforce (to enable the "Sign me in automatically" option), I updated login.aspx: select "Sign me in automatically" option by default and hide that option so that user no need to select that option.

Hope this will save time for someone.