Allow Windows Remote Assistance to communicate through a firewall
Because firewalls can restrict communication between your computer and the Internet, you might need to change firewall settings in order to use Windows Remote Assistance.
Open Windows Firewall by clicking the Start button , clicking Control Panel, clicking Security, and then clicking Windows Firewall.
Click Allow a program through Windows Firewall.
If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
Under Program or port, select the check box next to Remote Assistance, and then click OK.