Hi Souris,
Thank you for your reply. To address your questions, you can access the link (http://go.microsoft.com/fwlink/?linkId=144689) on a new session of your web browser. And yes, it is necessary to disable your firewall so that we could sort out the issue if your firewall causes it. To disable it, you might need to contact your firewall support team for assistance.
Windows Essentials includes Movie Maker, Photo Gallery, Writer and Windows Live Mail. Can you clarify when you said "how many program will be affected by the Windows Essential?".
I've also checked the link that you've provided (http://answers.microsoft.com/en-us/windowslive/forum/messenger-wlinstall/windows-live-id-sign-in-assistant-issue/251b4fee-32e7-4ab7-8eba-7756f70ba06b) and it has been locked.
We'll wait for your reply.
Regards.